Category Archives: History of Cartography

Renaissance science – XXVII

Early on in this series I mentioned that a lot of the scientific developments that took place during the Renaissance were the result of practical developments entering the excessively theoretical world of the university disciplines. This was very much the case in the mathematical sciences, where the standard English expression for the Renaissance mathematicus is mathematical practitioner. In this practical world, areas that we would now regard as separate disciples were intertwined is a complex that the mathematical practitioners viewed as one discipline with various aspects, this involved astronomy, cartography, navigation, trigonometry, as well as instrument and globe making. I have already dealt with trigonometry, cartography and astronomy and will here turn my attention to navigation, which very much involved the other areas in that list.

The so-called Age of Discovery or Age of Exploration, that is when Europeans started crossing the oceans and discovering other lands and other cultures, coincides roughly with the Renaissance and this was, of course the main driving force behind the developments in navigation during this period. Before we look at those developments, I want to devote a couple of lines to the terms Age of Discovery and Age of Exploration. Both of them imply some sort of European superiority, “you didn’t exist until we discovered you” or “your lands were unknown until we explored them.” The populations of non-European countries and continents were not sitting around waiting for their lands and cultures to be discovered by the Europeans. In fact, that discovery very often turned out to be highly negative for the discovered. The explorers and discoverers were not the fearless, visionary heroes that we tend to get presented with in our schools, but ruthless, often brutal chancers, who were out to make a profit at whatever cost.  This being the case the more modern Contact Period, whilst blandly neutral, is preferred to describe this period of world history.

As far as can be determined, with the notable exception of the Vikings, sailing in the Atlantic was restricted to coastal sailing before the Late Middle Ages. Coastal sailing included things such as crossing the English Channel, which, archaeological evidence suggests, was done on a regular basis since at least the Neolithic if not even earlier. I’m not going to even try to deal with the discussions about how the Vikings possibly navigated. Of course, in other areas of the world, crossing large stretches of open water had become common place, whilst the European seamen still clung to their coast lines. Most notable are the island peoples of the Pacific, who were undertaking long journeys across the ocean already in the first millennium BCE. Arab and Chinese seamen were also sailing direct routes across the Indian Ocean, rather than hugging the coastline, during the medieval period. It should be noted that European exploited the navigation skills developed by these other cultures as they began to take up contact with the other part of the world. Vasco da Gamma (c. 1460–1524) used unidentified local navigators to guide his ships the first time he crossed the Indian Ocean from Africa to India. On his first voyage of exploration of the Pacific Ocean from 1768 to 1771, James Cook (1728–1779) used the services of the of the Polynesian navigator, Tupaia (c. 1725–1770), who even drew a chart, in cooperation with Cook, Joseph Banks, and several of Cooks officer, of his knowledge of the Pacific Ocean. 

Tupaia’s map, c. 1769 Source: Wikimedia Commons

There were two major developments in European navigation during the High Middle Ages, the use of the magnetic compass and the advent of the Portolan chart. The Chinese began to use the magnetic properties of loadstone, the mineral magnetite, for divination sometime in the second century BCE. Out of this they developed the compass needle over several centuries. It should be noted that for the Chinese, the compass points South and not North. The earliest Chinese mention of the use of a compass for navigation on land by the military is before 1044 CE and in maritime navigation in 1117 CE.

Diagram of a Ming Dynasty (1368–1644) mariner’s compass Source: Wikimedia Commons

Alexander Neckam (1157–1219) reported the use of the compass for maritime navigation in the English Channel in his manuscripts De untensilibus and De naturis rerum, written between 1187 and 1202.

The sailors, moreover, as they sail over the sea, when in cloudy whether they can no longer profit by the light of the sun, or when the world is wrapped up in the darkness of the shades of night, and they are ignorant to what point of the compass their ship’s course is directed, they touch the magnet with a needle, which (the needle) is whirled round in a circle until, when its motion ceases, its point looks direct to the north.

This and other references to the compass suggest that it use was well known in Europe by this time.

A drawing of a compass in a mid 14th-century copy of Epistola de magnete of Peter Peregrinus. Source: Wikimedia Commons

The earliest reference to maritime navigation with a compass in the Muslim world in in the Persian text Jawāmi ul-Hikāyāt wa Lawāmi’ ul-Riwāyāt (Collections of Stories and Illustrations of Histories) written by Sadīd ud-Dīn Muhammad Ibn Muhammad ‘Aufī Bukhārī (1171-1242) in 1232. There is still no certainty as to whether there was a knowledge transfer from China to Europe, either direct or via the Islamic Empire, or independent multiple discovery. Magnetism and the magnetic compass went through a four-hundred-year period of investigation and discovery until William Gilbert (1544–1603) published his De magnete in 1600. 

De Magnete, title page of 1628 edition Source: Wikimedia Commons

The earliest compasses used for navigation were in the form of a magnetic needle floating in a bowl of water. These were later replaced with dry mounted magnetic needles. The first discovery was the fact that the compass needle doesn’t actually point at the North Pole, the difference is called magnetic variation or magnetic declination. The Chinese knew of magnetic declination in the seventh century. In Europe the discovery is attributed to Georg Hartmann (1489–1564), who describes it in an unpublished letter to Duke Albrecht of Prussia. However, Georg von Peuerbach (1423–1461) had already built a portable sundial on which the declination for Vienna is marked on the compass.

NIMA Magnetic Variation Map 2000 Source: Wikimedia Commons

There followed the discovery that magnetic declination varies from place to place. Later in the seventeenth century it was also discovered that declination also varies over time. We now know that the Earth’s magnetic pole wanders, but it was first Gilbert, who suggested that the Earth is a large magnet with poles. The next discovery was magnetic dip or magnetic inclination. This describes the fact that a compass needle does not sit parallel to the ground but points up or down following the lines of magnetic field. The discovery of magnetic inclination is also attributed to Georg Hartmann. The sixteenth century English, seaman Robert Norman rediscovered it and described how to measure it in his The Newe Attractive (1581) His work heavily influenced Gilbert. 

Illustration of magnetic dip from Norman’s book, The Newe Attractive Source: Wikimedia Commons

The Portolan chart, the earliest known sea chart, emerged in the Mediterranean in the late thirteenth century, not long after the compass, with which it is closely associated, appeared in Europe. The oldest surviving Portolan, the Carta Pisana is a map of the Mediterranean, the Black Sea and part of the Atlantic coast.

Source: Wikimedia Commons

The origins of the Portolan chart remain something of a mystery, as they are very sophisticated artifacts that appear to display no historical evolution. A Portolan has a very accurate presentation of the coastlines with the locations of the major harbours and town on the coast. Otherwise, they have no details further inland, indicating that they were designed for use in coastal sailing. A distinctive feature of Portolans is their wind roses or compass roses located at various points on the charts. These are points with lines radiating outwards in the sixteen headings, on later charts thirty-two, of the mariner’s compass.

Central wind rose on the Carta Pisana

Portolan charts have no latitude or longitude lines and are on the so-called plane chart projection, which treats the area being mapped as flat, ignoring the curvature of the Earth. This is alright for comparatively small areas, such as the Mediterranean, but leads to serious distortion, when applied to larger areas.

During the Contact Period, Portolan charts were extended to include the west coast of Africa, as the Portuguese explorers worked their way down it. Later, the first charts of the Americas were also drawn in the same way. Portolan style charts remained popular down to the eighteenth century.

Portolan chart of Central America c. 1585-1595 Source:

A central problem with Portolan charts over larger areas is that on a globe constant compass bearings are not straight lines. The solution to the problem was found by the Portuguese cosmographer Pedro Nunes (1502–1578) and published in his Tratado em defensam da carta de marear (Treatise Defending the Sea Chart), (1537).

Image of Portuguese mathematician Pedro Nunes in Panorama magazine (1843); Lisbon, Portugal. Source: Wikimedia Commons

The line is a spiral known as a loxodrome or rhumb lines. Nunes problem was that he didn’t know how to reproduce his loxodromes on a flat map.

Image of a loxodrome, or rhumb line, spiraling towards the North Pole Source: Wikimedia Commons

The solution to the problem was provided by the map maker Gerard Mercator (1512–1594), when he developed the so-called Mercator projection, which he published as a world map, Nova et Aucta Orbis Terrae Descriptio ad Usum Navigantium Emendate Accommodata (New and more complete representation of the terrestrial globe properly adapted for use in navigation) in 1569.

Source: Wikimedia Commons
The 1569 Mercator world map Source: Wikimedia Commons.

On the Mercator projection lines of constant compass bearing, loxodromes, are straight lines. This however comes at a price. In order to achieve the required navigational advantage, the lines of latitude on the map get further apart as one moves away from the centre of projection. This leads to an area distortion that increases the further north or south on goes from the equator. This means that Greenland, slightly more than two million square kilometres, appear lager than Africa, over thirty million square kilometres.

Mercator did not publish an explanation of the mathematics used to produce his projection, so initially others could reproduce it. In the late sixteenth century three English mathematicians John Dee (1527–c. 1608), Thomas Harriot (c. 1560–1621), and Edward Wright (1561–1615) all individually worked out the mathematics of the Mercator projection. Although Dee and Harriot both used this knowledge and taught it to others in their respective functions as mathematical advisors to the Muscovy Trading Company and Sir Walter Raleigh, only Wright published the solution in his Certaine Errors in Navigation, arising either of the Ordinarie Erroneous Making or Vsing of the Sea Chart, Compasse, Crosse Staffe, and Tables of Declination of the Sunne, and Fixed Starres Detected and Corrected. (The Voyage of the Right Ho. George Earle of Cumberl. to the Azores, &c.) published in London in 1599. A second edition with a different, even longer, title was published in the same year. Further editions were published in 1610 and 1657. 

Source: Wikimedia Commons
Wright explained the Mercator projection with the analogy of a sphere being inflated like a bladder inside a hollow cylinder. The sphere is expanded uniformly, so that the meridians lengthen in the same proportion as the parallels, until each point of the expanding spherical surface comes into contact with the inside of the cylinder. This process preserves the local shape and angles of features on the surface of the original globe, at the expense of parts of the globe with different latitudes becoming expanded by different amounts. The cylinder is then opened out into a two-dimensional rectangle. The projection is a boon to navigators as rhumb lines are depicted as straight lines. Source: Wikimedia Commons

His mathematical solution for the Mercator projection had been published previously with his permission and acknowledgement by Thomas Blundeville (c. 1522–c. 1606) in his Exercises (1594) and by William Barlow (died 1625) in his The Navigator’s Supply (1597). However, Jodocus Hondius (1563–1612) published maps using Wright’s work without acknowledgement in Amsterdam in 1597, which provoked Wright to publish his Certaine Errors. Despite its availability, the uptake on the Mercator projection was actually very slow and it didn’t really come into widespread use until the eighteenth century.

Wright’s “Chart of the World on Mercator’s Projection” (c. 1599), otherwise known as the Wright–Molyneux map because it was based on the globe of Emery Molyneux (died 1598) Source: Wikimedia Commons

Following the cartographical trail, we have over sprung a lot of developments in navigation to which we will return in the next episode. 


Filed under History of Cartography, History of Mathematics, History of Navigation, Renaissance Science

Renaissance science – XXVI

I wrote a whole fifty-two-part blog post series on The Emergence of Modern Astronomy, much of which covered the same period as this series, so I’m not going to repeat it here. However, an interesting question is, did the developments in astronomy during the Humanist Renaissance go hand in hand with humanism and to what extent, or did the two movements run parallel in time to each other without significant interaction? 

The simple answer to my own questions is yes, humanism and the emergence of modern astronomy were very closely interlinked in the period between 1400 and the early seventeenth century. This runs contrary to a popular conception that the Humanist Renaissance was purely literary and in no way scientific. In what follows I will briefly sketch some of that interlinking. 

To start, two of the driving forces behind the desire to renew and improve astronomy, the rediscovery of Ptolemaic mathematics-based cartography and the rise in importance of astrology were very much part of the Humanist Renaissance, as I have already documented in earlier episodes of this series. It is not a coincidence that many of the leading figures in the development of modern astronomy were also involved, either directly or indirectly, in the new cartography. Also, nearly all of them were active astrologers. 

Turning to the individual astronomers, the man, who kicked off the debate on the astronomical status of comets, a debate that, I have shown, played a central role in the evolution of modern astronomy, Paolo dal Pozzo Toscanelli (1397–1482) a member of the Florentine circle of prominent humanist scholars that included Filippo Brunelleschi, Marsilio Ficino, Leon Battista Alberti and Cardinal Nicolaus Cusanus, all of whom have featured in earlier episodes of this series.

Paolo dal Pozzo Toscanelli Source: Wikimedia Commons

Toscanelli, who is best known as the cosmographer, who supplied Columbus with a misleading world map, was one of those who met the Neoplatonic philosopher Georgius Gemistus Pletho (c. 1355–c. 1452) at the Council of Florence. Pletho introduced Toscanelli to the work of the Greek geographer Strabo (c. 64 BCE–c. 24 CE), which was previously unknown in Italy. 

Turning to the University of Vienna and the so-called First Viennese School of Mathematics, already during the time of Johannes von Gmunden (c. 1380–1442) and Georg Müstinger (before 1400–1442), Vienna had become a major centre for the new cartography as well as astronomy. However, it is with the next generation that we find humanist scholars at work. Toscanelli’s unpublished work on comets might have remained unknown if it hadn’t been for Georg von Peuerbach (1423–1461). As a young man Peuerbach had travelled extensively in Italy and become acquainted with the circle of humanists to which Toscanelli belonged. He shared an apartment in Rome with Cusanus and personally met and exchanged ideas with Toscanelli. Returning to Vienna he lectured on poetics and took a leading role in reviving classical Greek and Latin literature, a central humanist concern. Today he is, of course, better known for his work as an astronomer and as the teacher of Johannes Müller, better known Regiomontanus.

First page of Peuerbach’s Theoricae novae planetarum in the Manuscript Krakau, Biblioteca Jagiellońska, Ms. 599, fol. 1r (15th century) Source: Wikimedia Commons

Regiomontanus (1436–1476) became a member of the familia (household) of the leading Greek humanist scholar Basilios Bessarion (1403–1472), a pupil of Pletho. He travelled with Bessarion through Italy, working as his librarian finding and copying Latin and Greek manuscripts on astronomy, astrology and mathematics for Bessarion’s library. Bessarion had taught him Greek for this purpose. Leaving Bessarion’s service Regiomontanus served as librarian for the humanist scholars, János Vitéz Archbishop of Esztergom (c. 1408–1472) a friend of Peuerbach’s and then Matthias Corvinus (1443–1490) King of Hungary. 

Regiomontanus woodcut from the 1493 Nuremberg Chronicle Source: Wikimedia Commons

When Regiomontanus left Hungary for Nürnberg he took a vast collection of Geek and Latin manuscripts with him, with the intention of printing them and publishing them. At the same time applying humanist methods of philology to free them of their errors accumulated through centuries of copying and recopying. A standard humanist project as was the Epitome of Ptolemaeus that he and Peuerbach produced under the stewardship of Bessarion.

The so-called Second Viennese School of mathematics was literally founded by a humanist, when Conrad Celtis (1459–1508) took the professors of mathematics Andreas Stiborius (1464–1515) and Johann Stabius (before 1468–1522), along with the student Georg Tanstetter (1482–1535) from Ingolstadt to Vienna, where he founded his Collegium poetarum et mathematicorum, that is a college for poetry and mathematics, in 1497. Ingolstadt had established the first ever German chair for mathematics to teach astrology to medical students, also basically a humanist driven development.

Conrad Celtis: In memoriam by Hans Burgkmair the Elder, 1507
Source: Wikimedia Commons

The wind of humanism was strong in Vienna, where Peter Apian (1495–1552) was Tanstetter’s star pupil becoming like his teacher a cosmographer, returning to Ingolstadt, where his star pupil was his own son Philipp (1531–1589), like his father a cosmographer. Philipp became professor in Tübingen, where he was Michael Mästlin’s teacher, instilling him with the Viennese humanism. As should be well known Mästlin was Kepler’s teacher.

Source: Wikimedia Commons

Back-tracking, we must consider the central figure of the emergence of modern astronomy, Nicolaus Copernicus (1473–1543). There are no doubts about Copernicus’ humanist credentials.

Copernicus holding lily-of-the-valley: portrait in Nicolaus Reusner’s Icones (1587) Source: Wikimedia Commons

He initially studied at the University of Krakow, the oldest humanist university in Europe north of the Italian border. He continued his education at various North Italian humanist universities, where he continued to learn his astronomy from the works of Peuerbach and Regiomontanus (as he had already done in Krakow) under the supervision of Domenico Maria da Novara (1454–1504) a Neoplatonist, who regarded himself as a student of Regiomontanus.

Domenico Maria da Novara Source Museo Galileo

In Northern Italy Copernicus received a full humanist education even learning Greek and some Hebrew. Establishing his humanist credentials, Copernicus published a Latin translation from the Greek of a set of 85 brief poems by the seventh century Byzantine historian Theophylact Somicatta, as Theophilacti scolastici Simocati epistolae morales, rurales et amatoriae interpretatione Latina in 1509. He also wrote some Greek poetry himself.


Copernicus is often hailed as the first modern astronomer but as many historians have pointed out, his initial intention, following the lead of Regiomontanus, was to restore the purity of Greek astronomy, a very humanist orientated undertaking. He wanted to remove the Ptolemaic equant point, which he saw as violating the Platonic ideal of uniform circular motion. De revolutionibus was modelled on Ptolemaeus’ Mathēmatikē Syntaxis, or more accurately on the Epytoma in almagesti Ptolemei of Peuerbach and Regiomontanus.

Tycho Brahe (1546–1601) was also heavily imbued with the humanist spirit. His elaborate, purpose-built home, laboratory, and observatory on the island of Hven, Uraniborg, was built in the style of the Venetian architect Andrea Palladio (1508–1580),

Portrait of Palladio by Alessandro Maganza Source: Wikimedia Commons

the most influential of the humanist architects, and was one of the earliest buildings constructed in the Renaissance style in Norther Europe.


All of the Early Modern astronomers from Toscanelli down to at least Tycho, and very much including Copernicus, were dedicated to the humanist ideal of restoring what they saw as the glory of classical astronomy from antiquity. Only incidentally did they pave a road that led away from antiquity to modern astronomy. 


Filed under History of Astronomy, History of Cartography, Renaissance Science

OHMS or everything you wanted to know about the history of trigonometry and didn’t know who to ask

When I was a kid, letters from government departments came in buff, manila envelopes with OHMS printed on the front is large, black, capital letters. This acronym stood for, On Her Majesty’s Service and earlier during Liz’s father’s reign (and no I’m not that old, although I was just born in his reign), On His Majesty’s Service, implying that civil servants worked directly for the monarch.  This was, of course, the origin of the title of Ian Fleming’s eleventh James Bond novel, On Her Majesty’s Secret Service

When I started learning trigonometry at school this acronym took on a whole new meaning as a mnemonic for the sine relation in right angle triangles, Opposite over Hypotenuse Means Sine. Recently it occurred to me that we had no mnemonic for the other trigonometric relations. Now in those days or even later when the trigonometry I was taught got more complex, I wasn’t aware of the fact that this mathematical discipline had a history. Now, a long year historian of mathematics, I am very much aware of the fact that trigonometry has a very complex, more than two-thousand-year history, winding its way from ancient Greece over India, the Islamic Empire and Early Modern Europe down to the present day. 

The Canadian historian of mathematics, Glen van Brummelen has dedicated a large part of his life to researching, writing up and publishing that history of trigonometry. The results of his labours have appeared in three volumes, over the years, The Mathematics of the Heavens and the Earth: The Early History of Trigonometry, Princeton University Press, Princeton and Oxford, 2009, Heavenly Mathematics: The Forgotten Art of Spherical Trigonometry, Princeton University Press, Princeton and Oxford, 2013 and most recently The Doctrine of TrianglesA History of Modern Trigonometry, Princeton University Press, Princeton and Oxford, 2021. He describes himself as the “best trigonometry historian, and the worst trigonometry historian”, as he is the only one[1]

A review of these three volumes could be written in one sentence, if you are interested in the history of trigonometry, then these three masterful volumes are essential. One really doesn’t need to say more, but in what follows I will give a brief sketch of each of the books. 

The Mathematics of the Heavens and the Earth: The Early History of Trigonometry delivers exactly what it says on the cover. The book opens with a brief but detailed introduction to the basics of spherical astronomy, because for a large part of the period covered, what we have is not the history of plane trigonometry, that’s the stuff we all learnt at school, but spherical trigonometry, that is the geometry of triangles on the surface of a sphere, which was developed precisely to do spherical astronomy. 

A friendly warning for potential readers this is not popular history but real, hardcore history of mathematics with lots of real mathematical examples worked through in detail. However, given the way Van Brummelen structures his narrative, it is possible to skip the worked examples and still get a strong impression of the historical evolution of the discipline. This is possible because Van Brummelen gives a threefold description of every topic that he elucidates. First comes a narrative, fairly non-technical, description of the topic he is discussing. This is followed by an English translation of a worked example from the historical text under discussion, followed in turn by a technical explication of the text in question in modern terminology. Van Brummelen’s narrative style is clear and straightforward meaning that the non-expert reader can get good understanding of the points being made, without necessarily wading through the intricacies of the piece of mathematics under discussion. 

The book precedes chronologically. The first chapter, Precursors, starts by defining what trigonometry is and also what it isn’t. Having dealt with the definitions, Van Brummelen moves onto the history proper dealing with things that preceded the invention of trigonometry, which are closely related but are not trigonometry. 

Moving on to Alexandrian Greece, Van Brummelen takes the reader through the beginnings of trigonometry starting with Hipparchus, who produced the first chord table linking angles to chords and arcs of circles, Moving on through Theodosius of Bithynia and Menelaus of Alexandria and the emergence of spherical trigonometry. He then arrives at Ptolemy his astronomy and geography. Ptolemy gets the longest section of the book, which given that everything that follows in some way flows from his work in logical. Here we also get two defining features of the book. The problem of calculating trigonometrical tables and what each astronomer or mathematician contributed to this problem and the trigonometrical formulas that each of them developed to facilitate calculations. 

From Greece we move to India and the halving of Hipparchus’ and Ptolemy’s chords to produce the sine function and later the cosine that we still use today. Van Brummelen takes his reader step for step and mathematician for mathematician through the developments of trigonometry in India. 

The Islamic astronomers took over the baton from the Indians and continued the developments both in astronomy and geography. It was Islamic mathematicians, who developed the plane trigonometry that we know today rather than the spherical trigonometry. As with much other mathematics and science, trigonometry came into medieval Europe through the translation movement out of Arabic into Latin. Van Brummelen traces the development in medieval Europe down to the first Viennese School of mathematics, John of Gmunden, Peuerbach, and Regiomontanus. This volume closes with Johannes Werner and Copernicus, with a promise of a second volume. 

In the book itself, the brief sketch above is filled out in incredible detail covering all aspects of the evolution of the discipline, the problems, the advances, the stumbling stones and the mathematicians and astronomers, who discovered each problem, solved, or failed to solve them. To call Van Brummelen comprehensive would almost be an understatement. Having finished this first volume, I eagerly awaited the promised second volume, but something else came along instead.

Having made clear in his first book that the emphasis is very much on spherical trigonometry rather than plane trigonometry, in his second book Van Brummelen sets out to explain to the modern reader what exactly spherical trigonometry is, as it ceased to be part of the curriculum sometime in the modern period. What we have in Heavenly Mathematics: The Forgotten Art of Spherical Trigonometry is a spherical trigonometry textbook written from a historical perspective. The whole volume is written in a much lighter and more accessible tone than The Mathematics of the Heavens and the Earth. After a preface elucidating the purpose of the book there follow two chapters, Heavenly Mathematics and Exploring the Sphere, which lay out and explain the basics in clear and easy to follow steps.

Next up, we have the historical part of the book with one chapter each on The Ancient Approach and The Medieval Approach. These chapters could be used as an aid to help understand the relevant sections of the authors first book. But fear not the reader must not don his medieval personality to find their way around the complexities of spherical trigonometry because following this historical guide we are led into the modern textbook.

The bulk of the book consists of five chapters, each of which deals in a modern style with an aspect of spherical trigonometry: Right Angle Triangles, Oblique Triangles, Areas, Angles and Polyhedra, Stereographic Projection, and finally Navigation by the Stars. The chapter on stereographic projection is particularly interesting for those involved with astrolabes and/or cartography. 

The book closes with three useful appendices. The first is on Ptolemy’s determination of the position of sun. The second is a bibliography of textbooks on or including spherical trigonometry with the very helpful indication, which of them are available on Google Books. The final appendix is a chapter by chapter annotated list of further reading on each topic. 

If you wish to up your Renaissance astrology game and use the method of directions to determine your date of death, which require spherical trigonometry to convert from one celestial coordinate system to another, then this is definitely the book for you. It is of course also a brilliant introduction for anybody, who wishes to learn the ins and outs of spherical trigonometry. 

I bought Van Brummelen’s first book when it was published, in 2009, and read it with great enthusiasm, but experienced a sort of coitus interruptus, when in stopped in the middle of the Renaissance, the period that interested me most. I was consoled by the author’s declaration that a second volume would follow, which I looked forward to with great expectations. Over the years those expectations dimmed, and I began to fear that the promised second volume would never appear, so I was overjoyed when the publication of The Doctrine of Triangles was announced this year and immediately placed an advanced order. I was not disappointed. 

The modern history of trigonometry continues where the early history left off, tracing the developments of trigonometry in Europe from Regiomontanus down to Clavius and Gunter in the early seventeenth century. There then follows a major change of tack, as Van Brummelen delves into the origins of logarithms.

Today in the age of the computer and the pocket calculator, logarithmic tables are virtually unknown, a forgotten relic of times past. I, however, grew up using my trusty four figure log tables to facilitate calculations in maths, physics, and chemistry. Now, school kids only know logarithms as functions in analysis. One thing that many, who had the pleasure of using log tables, don’t know is that Napier’s first tables were of the logarithms of trigonometrical factions in order to turn the difficult multiplications and divisions of sines, cosines et al in spherical trigonometry into much simpler additions and subtractions and therefore Van Brummelen’s detailed presentation of the topic.

Moving on, in his third chapter, Van Brummelen now turns to the transition of trigonometry as a calculation aid in spherical and plane triangles to trigonometrical functions in calculus. There where they exist in school mathematics today. Starting in the period before Leibniz and Newton, he takes us all the way through to Leonard Euler in the middle of the eighteenth century. 

The book now undergoes a truly major change of tack, as Van Brummelen introduces a comparative study of the history of trigonometry in Chinese mathematics. In this section he deals with the Indian and Islamic introduction of trigonometry into China and its impact. How the Chinese dealt with triangles before they came into contact with trigonometry and then the Jesuit introductions of both trigonometry and logarithms into China and to what extent this influenced Chinese geometry of the triangle. A fascinating study and an enrichment of his already excellent book.

The final section of the book deals with a potpourri of developments in trigonometry in Europe post Euler. To quote Van Brummelen, “A collection of short stories is thus more appropriate here than a continuous narrative.” The second volume of Van Brummelen’s history is just as detailed and comprehensive as the first. 

All three of the books display the same high level of academic rigour and excellence. The two history volumes have copious footnotes, very extensive bibliographies, and equally extensive indexes. The books are all richly illustrated with many first-class explanatory diagrams and greyscale prints of historical title pages and other elements of the books that Van Brummelen describes. All in all, in his three volumes Van Brummelen delivers a pinnacle in the history of mathematics that sets standards for all other historians of the discipline. He really does live up to his claim to be “the best historian of trigonometry” and not just because he’s the only one.

Coda: If the potential reader feels intimidated by the prospect of the eight hundred and sixty plus pages of the three volumes described here, they could find a gentle entry to the topic in Trigonometry: A Very Short Introduction (OUP, 2020), which is also authored by Van Brummelen, a sort of Van Brummelen light or Van Brummelen’s greatest hits.

In this he covers a wide range of trigonometrical topics putting them into their historical context. But beware, reading the Very Short Introduction could well lead to further consumption of Van Brummelen’s excellent work. 

[1] This is not strictly true as Van Brummelen has at least two predecessors both of who he quotes in his works. The German historian Anton von Braunmühl, who wrote several articles and a two volume Vorlesung über Geschichte der Trigonometrie (Leipzig, 1900/1903) and the American Sister Mary Claudia Zeller, The Development of Trigonometry from Regiomontanus to Pitiscus (Ann Arbor 1944)


Filed under History of Astronomy, History of Cartography, History of Islamic Science, History of Mathematics, History of Navigation

Renaissance Science – XXII

Perhaps surprisingly, land surveying as we know it today, a mathematical discipline utilising complex technological measuring instruments is very much a product of the practical mathematics of the Renaissance. Why surprisingly? Surveying is an ancient discipline that has its origins in humanity becoming settled many thousands of years ago. Ancient monuments such as the pyramids or Stonehenge definitely required some level of surveying in their construction and there are surviving documents from all literate ancient societies that refer to methods or the practice of surveying. 

All surveying uses some aspects of geometry and as Herodotus famously claimed geometry (Greek: geōmetría from geōmétrēs), which literally means measurement of earth or land, had its origins in Egyptian surveying for tax purposes. According to his account, King Sesostris divided all the lands in Egypt amongst its inhabitants in return for an annual rent. However, every year the Nile floods washing away the parts of the plots:

The country is converted into a sea, and nothing appears but the cities, which looked like islands in the Aegean. 

Those whose land had been lost objected to paying the rent, so Sesostris summoned those affected to appear before him.

Upon which, the king sent persons to examine, and determine by measurement the exact extent of the loss: and thenceforth only such a rent was demanded of him as was proportionate to the reduced size of his land. From this practice, I think, geometry first came to be known in Egypt, whence it passed into Greece.

According to legend, both Thales and Pythagoras, are reputed to have learnt their geometry in Egypt.

In all early cultures surveying was fairly primitive with measurements being made with ropes and measuring rods. In Egypt, surveyors were known as rope stretchers (harpedonaptai), the ropes used for measuring being stretched to avoid sagging.

A rope being used to measure fields. Taken from the Tomb of Menna, TT69. (c. 1500–1200 BCE) Source: Wikimedia Commons

Longer distances were either measured by estimation or by pacing. In ancient Egypt and Greece Bematistae (step measurer) where trained to walk with equal length paces and the historical records of Alexander the Great’s campaigns suggest that they were indeed highly accurate. This measuring of distances by pacing in reflected in our word mile, which is the Latin word for a thousand, mille, meaning a thousand paces.

The Latin for surveyor was agrimensores, meaning field measurers. They were also called gromatici after the groma a surveyor’s pole, an early instrument for determining lines at right angles to each other. 

The groma or gruma was a Roman surveying instrument. It comprised a vertical staff with horizontal cross-pieces mounted at right angles on a bracket. Each cross piece had a plumb line hanging vertically at each end. It was used to survey straight lines and right angles, thence squares or rectangles. They were stabilized on the high ground and pointed in the direction it was going to be used. The helper would step back 100 steps and place a pole. The surveyor would tell him where to move the pole and the helper would set it down.

(Lewis, M. J. T., Surveying instruments of Greece and Rome, McGraw Hill Professional, 2001, p. 120)
Staking out a right angle using a groma

Another instrument used for the same purpose was the dioptra. The dioptra was a sighting tube or, alternatively an alidade, that is a rod with a sight at each end, attached to a stand. If fitted with protractors, it could be used to measure angles. Hero from Alexandria wrote a whole book on this instrument and its use but there are doubts that the dioptra in the complex form described by Hero was actually used in field surveying.

Dioptra as described by Hero of Alexandria Source: Wikimedia Commons

The methods used by the Romans in field surveying were described in the works of technical authors such as Sextus Julius Frontinus (c. 40–103 CE) and Gaius Julius Hyginus (c. 64 BCE–17 CE).

All of the surveying described in antiquity was fairly small scale–measuring fields, determining boundaries, laying out military camps, etc–and geometrically centred on squares and rectangles. Cartography was done using astronomical determinations of latitude and longitude, whereby the latter was difficult, and distances estimated or paced. Nothing really changed in Europe during the medieval period. The surveying that was done was carried out using the same methods that the Romans had used. However, during the fifteenth century things began to change substantially and the first question is why?

The rediscovery of Ptolemaeus’ Geographia at the beginning of the fifteenth century, as described here, and the subsequent substantial increase in cartographical activity, as described here, played a major role, but as already stated above Ptolemaic cartography relied almost exclusively on astronomical methods and did not utilise field surveying. However, there was an increased demand for internal accuracy in maps that astronomical methods could not supply. Secondly, changes in land ownership led to an increased demand for accurate field surveying of estates that required more sophisticated methods than those of the agrimensores. Lastly, we have a good example of the knowledge crossover, typical for the Renaissance, as described in Episode V of this series. The surveyors of antiquity were artisans producing practical knowledge for everyday usage. In the Renaissance, university educated scholars began to interest themselves for this practical knowledge and make contributions to its development and it is these developments that we will now look at. 

The biggest change in surveying was the introduction of the simple geometrical figure the triangle into surveying, as Sebastian Münster, one of the most influential cosmographers (today we would say geographer) of the period, wrote in a German edition of his Cosmographia. Beschreibung aller Lender durch Sebastianum Münsterum in 1550:

Every thing you measure must be measured in triangles.

Actually, the theory of similar triangles, as explained in Euclid’s Elements, had been used in surveying in antiquity, in particular to determine the height of things or for example the width of a river. A method that I learnt as a teenager in the Boy Scouts.

What was new as we will see was the way that triangles were being used in surveying and that now it was the angles of the triangles that were measured and not the length of the sides, as in the similar triangles’ usage. We are heading towards the invention and usage of triangulation in surveying and cartography, a long-drawn-out process.

In his Ludi rerum mathematicarum (c. 1445), the architect Leon Battista Alberti describes a method of surveying by taking angular bearings of prominent points in the area he is surveying using a self-made circular protractor to create a network of triangles. He concludes by explaining that one only needs to the length of one side of one triangle to determine all the others. What we have here is an early description of a plane table surveying (see below) and step towards triangulation that, however, only existed in manuscript 

Alberti Ludi rerum mathematicarum 

Münster learnt his geometry from Johannes Stöffler (1452–1531), professor for mathematics in Tübingen, who published the earliest description of practical geometry for surveyors. In his De geometricis mensurationibus rerum (1513),

Johannes Stöffler Engraving from the workshop of Theodor de Brys, Source: Wikimedia Commons

Stöffler explained how inaccessible distances could be measured by measuring one side of a triangle using a measuring rod (pertica) and then observing the angles from either end of the measured stretch. However, most of the examples in his book are still based on the Euclidian concept of similar triangles rather than triangulation. In 1522, the printer publisher Joseph Köbel, who had published the Latin original, published a German version of Stöffler’s geometry book. 

Joseph Köbel Source: Wikimedia Commons

Both Peter Apian in his Cosmographia (1524) and Oronce Fine in his De geometria practica (1530) give examples of using triangles to measure distances in the same way as Stöffler.


Fine indicating that he knew of Stöffler’s book. Apian explicitly uses trigonometry to resolve his triangles rather than Euclidian geometry. Trigonometry had already been known in Europe in the Middle Ages but hadn’t been used before the sixteenth century in surveying. Fine, however, still predominantly used Euclidian methods in his work, although he also, to some extent, used trigonometry.

A very major development was the publication in 1533 of Libellus de locorum describendum ratione (Booklet concerning a way of describing places) by Gemma Frisius as an appendix to the third edition of Apian’s Cosmographia, which he edited, as he would all edition except the first. Here we have a full technical description of triangulation published for the first time. It would be included in all further editions in Latin, Spanish, French, Flemish, in what was the most popular and biggest selling manual on mapmaking and instrument making in the sixteenth and seventeenth centuries.

Source: Wikimedia Commons

1533 also saw the publication in Nürnberg by Johannes Petreius (c. 1497–1550) of Regiomontanus’s De triangulis omnimodis (On triangles of every kind) edited by the mapmaker and globe maker, Johannes Schöner (1477–1547).


This volume was originally written in 1464 but Regiomontanus died before he could print and publish it himself, although he had every intention of doing so. This was the first comprehensive work on trigonometry in Europe in the Early Modern Period, although it doesn’t cover the tangent, which Regiomontanus handled in his Tabula directionum (written 1467, published 1490), an immensely popular and oft republished work on astrology. 

Regiomontanus built on previous medieval works on trigonometry and the publication of his book introduces what Ivor Grattan Guinness has termed The Age of Trigonometry. In the sixteenth century it was followed by Rheticus’ separate publication of the trigonometrical section of Copernicus’s De revolutionibus, as De lateribus et angulis triangulorium in 1542. Rheticus (1514–1574) followed this in 1551 with his own Canon doctrinae triangulorum. This was the first work to cover all six trigonometric functions and the first to relate the function directly to triangles rather than circular arcs.

Source: Wikimedia Commons

Rheticus spent the rest of his life working on his monumental Opus Palatinum de Triangulis, which was, however, first published posthumously by his student Lucius Valentin Otho in 1596. Rheticus and Otho were pipped at the post by Bartholomaeus Pitiscus (1561–1613), whose Trigonometriasive de solutione triangulorum tractatus brevis et perspicuous was published in 1595 and gave the discipline its name.

Source: Wikimedia Commons

Pitiscus’ work went through several edition and he also edited and published improved and corrected editions of Rheticus’ trigonometry volumes. 

Through Gemma Frisius’ detailed description of triangulation and sixteenth century works on trigonometry, Renaissance surveyors and mapmakers now had the mathematical tools for a new approach to surveying. What they now needed were the mathematical instruments to measure distances and angles in the field and they were not slow in coming.

The measure a straight line of a given distance as a base line in triangulation surveyors still relied on the tools already used in antiquity the rope and the measuring rod. Ropes were less accurate because of elasticity and sagging if used for longer stretches. In the late sixteenth century, they began to be replaced by the surveyor’s chain, made of metal links but this also suffered from the problem of sagging due to its weight, so for accuracy wooden rods were preferred. 

A Gunter chain photographed at Campus Martius Museum. Source: Wikimedia Commons

In English the surveyor’s chain is usually referred to as Gunter’s chain after the English practical mathematician Edmund Gunter (1581–1626) and he is also often referred to erroneously as the inventor of the surveyor’s chain but there are references to the use of the surveyor’s chain in 1579, when Gunter was still a child. 

He did, however, produce what became a standardised English chain of 100 links, 66 feet or four poles, perches, or rods long, as John Ogilby (1600–1676) wrote in his Britannia Atlas in 1675:

…a Word or two of Dimensurators or Measuring Instruments, whereof the mosts usual has been the Chain, and the common length for English Measures 4 Poles, as answering indifferently to the Englishs Mile and Acre, 10 such Chains in length making a Furlong, and 10 single square Chains an Acre, so that a square Mile contains 640 square Acres…’

An English mile of 5280 feet was thus 80 chains in length and there are 10 chains to a furlong. An acre was 10 square chains. I actually learnt this antiquated system of measurement whilst still at primary school. The name perch is a corruption of the Roman name for the surveyor’s rod the pertica. 

To measure angles mapmakers and surveyors initially adopted the instruments developed and used by astronomers, the Jacob staff, the quadrant, and the astrolabe. An instrument rarely still used in astronomy but popular in surveying was the triquetum of Dreistab. The surveyors triquetum consists of three arms pivoted at two points with circular protractors added at the joints to measure angles and with a magnetic compass on the side to determine bearings. 

Surveyors then began to develop variants of the dioptra. The most notable of these, that is still in use today albeit highly modernised, was the theodolite, an instrument with sights capable of measuring angles both vertically and horizontally. The name first occurs in the surveying manual A geometric practice named Pantometria by Leonard Digges (c. 1515–c. 1559) published posthumously by his son Thomas (c. 1546–1595) in 1571.

Leonard Digges  A geometric practice named Pantometria Source

However, Digges’ instrument of this name could only measure horizontal angles. He described another instrument that could measure both vertical and horizontal angles that he called a topographicall instrument. Josua Habermehl, about whom nothing is known, but who was probably a relative of famous instrument maker Erasmus Habermehl (c. 1538–1606), produced the earliest known instrument similar to the modern theodolite, including a compass and tripod, in 1576. In 1725, Jonathan Sisson (1690–1747) constructed the first theodolite with a sighting telescope.

Theodolite 1590 Source:

A simpler alternative to the theodolite for measuring horizontal angles was the circumferentor. This was a large compass mounted on a plate with sights, with which angles were measured by taking their compass bearings.

18th century circumferentor

Instruments like the triquetum and the circumferentor were most often used in conjunction of another new invention, the plane table. Gemma Frisius had already warned in his Libellus de locorum describendum rationeof the difficulties of determining the lengths of the sides of the triangles in triangulation using trigonometry and had described a system very similar to the plane table in which the necessity for these calculation is eliminated. 

Surveying with plane table and surveyor’s chain

The plane table is a drawing board mounted on a tripod, with an alidade. Using a plumb bob, the table is centred on one end of a baseline, levelled by eye or after its invention (before 1661) with a spirit level, and orientated with a compass. The alidade is placed on the corresponding end of the scaled down baseline on the paper on the table and bearings are taken of various prominent features in the area, the sight lines being drawn directly on the paper. This procedure is repeated at the other end of the baseline creating triangles locating the prominent figures on the paper without having to calculate.

Philippe Danfrie (c.1532–1606) Surveying with a plane table

As with the theodolite there is no certain knowledge who invented the plane table. Some sources attribute the invention of the plane table to Johannes Praetorius (1537–1616), professor for mathematics at the University of Altdorf, as claimed by his student Daniel Schwentner (1585–1636). However, there was already a description of the plane table in “Usage et description de l’holomètre”, by Abel Foullon (c. 1514–1563) published in Paris in 1551. It is obvious from his description that Foullon hadn’t invented the plane table himself. 

The plane table is used for small surveys rather than mapmaking on a large scale and is not triangulation as described by Gemma Frisius. Although the Renaissance provided the wherewithal for full triangulation, it didn’t actually get used much for mapping before the eighteenth century. At the end of the sixteenth century Tycho Brahe carried out a triangulation of his island of Hven, but the results were never published. The most notable early use was by Willebrord Snel (1580–1626) to measure one degree of latitude in order to determine the size of the earth in 1615. He published the result in his Eratosthenes batavus in Leiden in 1617. He then extended his triangulation to cover much of the Netherlands.

Snel’s Triangulation of the Dutch Republic from 1615 Source: Wikimedia Commons

In the late seventeenth century Jean Picard (1620–1682) made a much longer meridian measurement in France using triangulation. 

Picard’s triangulation and his instruments

In fourteen hundred European surveyors were still using the same methods of surveying as the Romans a thousand years earlier but by the end of the seventeenth century when Jean-Dominique Cassini (1625–1712) began the mapping of France that would occupy four generations of the Cassini family for most of the eighteenth century, they did so with the fully developed trigonometry-based triangulation that had been developed over the intervening three hundred years. 


Filed under History of Astronomy, History of Cartography, History of Geodesy, History of Mathematics, History of science, Renaissance Science

Renaissance Science – XVII

As we saw in the last episode, Ptolemaeus’ Geographia enjoyed a strong popularity following its rediscovery and translation into Latin from Greek at the beginning of fifteenth century, going through at least five printed editions before the end of the century. The following century saw several important new translation and revised editions both in Latin and in the vernacular. This initial popularity can at least be partially explained by the fact that Ptolemaeus’ Mathēmatikē Syntaxis and his Tetrabiblos, whilst not without rivals, were the dominant books in medieval astronomy and astrology respectively. But the Geographia, although, as explained in the previous episode, in some senses related to the other two books, was a book about mapmaking. So how did affect European mapmaking in the centuries after its re-emergence? To answer this question, we first need to look at medieval European, terrestrial mapmaking.

Mapmaking was relatively low level during the medieval period before the fifteenth century and although there were certainly more, only a very small number of maps have survived. These can be divided into three largely distinct categories, regional and local maps, Mappa Mundi, and portolan charts. There are very few surviving regional or local maps from the medieval period and of those the majority are from 1350 or later, mapmaking was obviously not very widespread in the early part of the Middle Ages. There are almost no maps of entire countries, the exceptions being maps of Palestine,

Map of Palestine according to Burchard of Mount Sion Manuscript c. 1300 entitled: “De more vivendi diversarum gentium, secundum Hieronymum in libro II contra Iovinianum, quae illis cibariis vesci solent, quibus abundant” Source: Wikimedia Commons

the Matthew Paris and Gough maps of Britain,

The most developed of Matthew Paris’s four maps of Britain 13th century (Cotton MS Claudius D VI, fol. 12v). The work is organised around a central north-south itinerary from Dover to Newcastle. The crenellations of both the Antonine Wall and Hadrian’s Wall can be seen in the upper half of the drawing. British Library, London. via Wikimedia Commons

and Nicolas of Cusa’s maps of Germany and central Europe. 

Nicolas of Cusa map of central Europe printed edition 1491 Germanisches Nationalmuseum Nürnberg via Wikimedia Commons

The Mappa Mundi are the medieval maps of the known world. These range from very simple schematic diagrams to the full-blown presentations of the oikoumenikos, the entire world as known to European antiquity, consisting of the three continents of Asia, Europe, and Africa. The sketch maps are mostly of two different types, the zonal maps, and the T-O maps. 

The zonal maps show just the eastern hemisphere divided by lines into the five climata or climate zones, as defined by Aristotle. These are the northern frigid zone, the northern temperate zone, the equatorial tropical zone, the southern temperate zone, and the southern frigid zone, of which the Greek believed only the two temperate zones were habitable. In the medieval period, zonal maps are mostly found in copies of Macrobius’ Commentarii in Somnium Scipionis (Commentary on Cicero’s Dream of Scipio).

Macrobius zonal world map c. 1050 Source: British Library

T-O sketch maps show a diagrammatic presentation of the three know continents, Asia, Europe, and Africa enclosed within a double circle representing the ocean surrounding oikoumenikos. The oikoumenikos is orientated, that is with east at the top and is divided into three parts by a T consisting of the Mediterranean, the Nile, and the Danube, with the top half consisting of Asia and the bottom half with Europe on the left and Africa on the right. T-O maps have their origin in the works of Isidore, his De Natura Rerum and Etymologiae. He writes in De Natura Rerum

So the earth may be divided into three sides (trifarie), of which one part is Europe, another Asia, and the third is called Africa. Europe is divided from Africa by a sea from the end of the ocean and the Pillars of Hercules. And Asia is divided from Libya with Egypt by the Nile… Moreover, Asia – as the most blessed Augustine said – runs from the southeast to the north … Thus we see the earth is divided into two to comprise, on the one hand, Europe and Africa, and on the other only Asia

This T and O map, from the first printed version of Isidore’s Etymologiae, identifies the three known continents as populated by descendants of Sem, Iafeth and Cham. Source: Wikimedia Commons

For most people the term Mappa Mundi evokes the large circular, highly coloured maps of the oikoumenikos, packed with symbols and text such as the Hereford and Ebstorf maps, rather that the small schematic ones.

The Hereford Mappa Mundi, about 1300, Hereford Cathedral, England Source: Wikimedia Commons

These are basically T-O maps but appear to be geographically very inaccurate. This is because although they give an approximate map of the oikoumenikos, they are not intended to be geographical maps, as we understand them today. So, what are they? The clue can be found in the comparatively large number of regional maps of Palestine, the High Middle Ages is a period where the Catholic Church and Christianity dominated Europe and the Mappa Mundi are philosophical maps depicting the world of Christianity. 

Recreation of the Ebstorf Map of about 1235; the original was destroyed by wartime bombing Source: Wikimedia Commons

These maps are literally orientated, that is East at the top and have Jerusalem, the hub of the Christian world, at their centre. The Hereford map has the Garden of Eden at the top in the east, whereas the Ebstrof map, has Christ’s head at the top in the east, his hands on the sides north and south and his feet at the bottom in the south, so that he is literally holding the world. The much smaller Psalter map has Christ above the map in the east blessing the world.

Psalter world map, ca. 1260 British Library via Wikimedia Commons

These are not maps of the world but maps of the Christian world. The illustrations and cartouches scattered all over the maps elucidate a motley collection of history, legends and myths that were common in medieval Europe. These Mappa Mundi are repositories of an extensive collection of information, but not the type of geographical knowledge we expect when we hear the word map.

The third area of medieval mapping is the portolan charts, which pose some problems. These are nautical charts that first appeared in the late thirteenth century in the Mediterranean and then over the centuries were extended to other sea areas. They display a detailed and surprising accurate stretch of coastline and are covered with networks of rhumb lines showing compass bearings.

The oldest original cartographic artifact in the Library of Congress: a portolan nautical chart of the Mediterranean. Second quarter of the 14th century. Source: Wikimedia Commons

Portolan charts have no coordinates. The major problem with portolan charts is their origin. They display an accuracy, at the time, unknown in other forms of mapping but the oldest known charts are fully developed. There is no known development leading to this type of mapping i.e., there are no known antecedent charts. The second problem is the question, are they based on a projection? There is some discussion on this topic, but the generally accepted view is that they are plate carrée or plane chart projection, which means that the mapmakers assumes that the area to be map is flat. This false assumption is OK if the area being mapped is comparatively small but leads to serios problems of distortion, when applied to larger areas.

Maps, mapping, and map making began to change radically during the Renaissance and one of the principle driving factors of that change was the rediscovery of Ptolemaeus’ Geographia. It is important to note that the Geographia was only one factor and there were several others, also this process of change was gradual and drawn out. 

What did the Geographia bring to medieval mapmaking that was new? It reintroduced the concept of coordinates, longitude and latitude, as well as map projection. As Ptolemaeus points out the Earth is a sphere, and it is mathematically impossible to flatten out the surface of a sphere onto a flat sheet without producing some sort of distortion. Map projections are literally what they say they are, they are ways of projecting the surface of the sphere onto a flat surface. There are thousands of different projections, and the mapmaker has to choose, which one is best suited to the map that he is drawing. As Ptolemaeus points out for a map of the world, it is actually better not the draw it on a flat sheet but instead to draw it on a globe. 

The Geographia contains instructions for drawing a map of the Earth i.e., the oikoumenikos, and for regional maps. For his regional maps Ptolemaeus uses the plate carrée or plane chart projection, the invention of which he attributes to his contemporary Marinus of Tyre. In this projection, the lines of longitude (meridians) and latitude (parallels) are parallel sets of equally spaced lines. For maps of the world, he describes three other projections. The first of these was a simple conic projection in which the surface of the globe is projected onto a cone, tangent to the Earth at the 36th parallel. Here the meridians are straight lines that tend to close towards the poles, while the parallels are concentric arcs. The second was a modified cone projection where the parallels are concentric arcs and the meridians curve inward towards the poles.

Ptolemaeus’ projection I above and II below Source: Marjo T Nurminen, “The Mapmakers’ World”, Pool of London Press, 2014

His third projection, a perspective projection, needn’t interest us here as it was hardly used, however the art historian Samuel Y Edgerton, who died this year, argued that the rediscovery of Ptolemaeus’ third projection at the beginning of the fifteenth century was the impulse that led to Brunelleschi’s invention of linear perspective.

A mid-15th century Florentine Ptolemaic map of the world Ptolemy’s 1st projection.
A printed Ptolemaic world map using his 2nd projection Johannes Schnitzer (1482). Source: Wikimedia Commons

From very early on Renaissance cosmographers began to devise and introduce new map projections, at the beginning based on Ptolemaeus’ projections. For example, in his In Hoc Opere Haec Continentur Nova Translatio Primi Libri Geographicae Cl Ptolomaei, from 1514, Johannes Werner (1468–1522) introduced the heart shaped or cordiform projection devised by his friend and colleague Johannes Stabius (1540–1522), now know as the Werner-Stabius projection. This was used by several mapmakers in the sixteenth century, perhaps most famously by Oronce Fine (1494–1555) in 1536.

Oronce Fine World Map 1536 Source: Wikimedia Commons

Francesco Rosselli (1455–died before 1513) introduced an oval projection with his world map of 1508

World Map oval by Francesco Rosselli, copper plate engraving on vellum 1508, National Maritime Museum via Wikimedia Commons

It should be noted that prior to the rediscovery of the Geographia, map projection was not unknown in medieval Europe, as the celestial sphere engraved on the tympans or climata of astrolabes are created using a stereographic projection.

Animation showing how celestial and geographic coordinates are mapped on an astrolabe’s tympan through a stereographic projection. Hypothetical tympan (40° north latitude) of a 16th-century European planispheric astrolabe. Source: Wikimedia Commons

The first wave of Renaissance mapmaking concerned the Geographia itself. As already noted, in the previous episode, the first printed edition with maps appeared in Bologna in 1477. This was closely followed by one produced with copper plate engravings, which appeared in Rome in 1478. An edition with maps printed with woodblocks in Ulm in 1482. Another edition, using the same plates as the 1478 edition appeared in Rome in 1490. Whereas the other fifteenth century edition only contained the twenty-seven maps described by Ptolemaeus in his text, the Ulm edition started a trend, that would continue in later editions, of adding new contemporary maps to the Geographia. These editions of the Geographia represent the advent of the modern atlas, to use an anachronistic term, an, at least nominally, uniform collection of maps with text bound together in book. It would be approximately a century before the first real modern atlas, that of Abraham Ortelius, would be published, but as Elizabeth Eisenstein observed, the European mapmakers first had to catch up with Ptolemaeus. 

These printed edition of the Geographia also illustrate another driving force behind the radical increase in mapmaking during the Renaissance, the invention of the printing press. The invention of the printing press and the development of cooper plate engraving, as well as woodblock printing meant that the multiple reproduction of maps and plans became much easier and also much cheaper. 

Another factor behind the increase in mapmaking was the so-called age of discovery. The Portuguese had been working their way down the coast of Africa throughout the fifteenth century and Bartolomeu Dias (c. 1450–1500) rounded the southern tip of Africa, for the first time in 1488, paving the way for the first trip by a European by an ocean route to India by Vasco da Gama (c. 1460s–1524) in 1497–99. Of course, as every school kid knows “In fourteen hundred and ninety-two, Columbus sailed the ocean blue” or put for formally the Genoese seaman Christopher Columbus (1451–1506) undertook his first voyage to Asia in service of the Spanish Crown in 1492 and accidentally discovered the so-called forth continent, which Martin Waldseemüller (c. 1475–1520) and Matthias Ringmann (c. 1482–1511) incorrectly christened America in 1507, in honour of Amerigo Vespucci (1451–1512), whom they falsely believed to be the discoverer of the new, to Europeans, continent. 

The initial maps produced by the European discovery expedition carried the portolan chart tradition out from the Mediterranean into the Atlantic Ocean, down the coast of Africa and eventually across the Atlantic to the coasts of the newly discovered Americas.

Kunstmann II or Four Finger Map. Dating from the period circa 1502‒6 Source: World Digital Library

Although not really suitable for maps of large areas the tradition of the portolan charts survived well into the seventeenth century. In 1500, Juan de la Cosa (c. 1450–1510) produced a world portolan chart. This is the earliest known map to include a representation of the New World.

Juan de la Cosa world map 1500

The 1508 edition of the Geographia published in Rome was the first edition to include the European voyages of exploration to the New World. The world map drawn by the Flemish mapmaker Johan Ruysch (c. 1460–1533), who had himself sailed to America, includes the north coast of South America and some of the West Indian islands. On the other side it also includes eastern Asia with China indicated by a city marked as Cathaya, however, Japan (Zinpangu) is not included.

Ruysch’s 1507 map of the world. Source: Wikimedia Commons

Ruysch’s map bears a strong resemblance to the Cantarini-Rosselli world map published in Venice or Florence in 1506. Drawn by Giovanni Matteo Conarini (died 1507) and engraved by Francesco Rosselli (1455–died before 1513), which was the earliest known printed map containing the New World. The Ruysch map and the Cantarini-Rosselli probably shared a common source. 

The most famous map showing the newly discovered fourth continent is, of course, the Waldseemüller world map of 1507, which gave America its name.

Universalis Cosmographia, the Waldseemüller wall map dated 1507, depicts America, Africa, Europe, Asia, and the Oceanus Orientalis Indicus separating Asia from the Americas. Source: Wikimedia Commons

Of interest here is the fact that Waldseemüller apparently also published a small, printed globe of his wall map, which is the earliest known printed globe.

Waldseemüller globe gores of 1507 Source: Wikimedia Commons

The age of the modern terrestrial globe was ushered in by the earliest known, surviving manuscript globe produced by Martin Behaim (1549-1507) in 1493. Because he had supposedly taken part on Portuguese expedition along the African coast, he was commissioned, by the city council of Nürnberg, during a visit to the city of his birth,  to produce a globe and a large wall map of the world for the council chamber. The map no longer exists. Behaim’s main source for his maps was Ptolemaeus’ Geographia.

Behaim Globe Germanisches Nationalmuseum Nürnberg

Waldseemüller’s globe had apparently little impact and only four sets of globe gores still exist but none of the finished globes. The person who really set the production of printed globes in motion was the Nürnberger mathematicus Johannes Schöner (1477–1547), who produced his first printed terrestrial globe in 1515, which did much to cement the name America given to the fourth continent by Waldseemüller and Ringmann. Schöner was the owner of the only surviving copy of the Waldseemüller map.

Schöner Terrestrial Globe 1515, Historisches Museum Frankfurt

Like Behaim and Waldseemüller, Schöner’s main source of information was Ptolemaeus’ Geographia, of which he owned a heavily annotated copy, and which like them he supplemented with information from various other sources. In 1517, he also produced a matching, printed celestial globe, establishing the tradition of matching globe pairs that persisted down to the nineteenth century.

Schöner was not the only Nürnberger mathematicus, who produced globes. We know that Georg Hartmann (1489–1564), who acted as Schöner’s globe salesman in Nürnberg, when Schöner was still living in Kirchehrenbach, also manufactured globes, but none of his have survived. Although they weren’t cheap, it seems that Schöner’s globes sold very well, well enough to motivate others to copy them. Both Waldseemüller, with his map, and Schöner, with his globes, published an accompanying cosmographia, a booklet, consisting of instructions for use as well as further geographical and historical information. An innovative printer/publisher in Louvain reprinted Schöner’s cosmographia, Lucullentissima quaedam terrae totius descriptio, and commissioned Gemma Frisius (1508–1555) to make a copy of Schöner’s globe to accompany it. Frisius became a globe maker, as did his one-time student and assistant Gerard Mercator (1512-1594), who went on to become the most successful globe maker in Europe.

Gemma Frisius globe 1536

Both Willem Janszoon Blaeu (1571–1638) and Jodocus Hondius (1563–1612) emulated Mercator’s work establishing the Netherlands as the major European map and globe making centre in the seventeenth century.

Another factor that contributed to the spread of map making in the sixteenth century was the Renaissance development of realism in painting. This was a combination of the invention of linear perspective during the fifteenth century on the one hand and on the other, the development of Naturalism beginning in the late fourteenth century in the Netherlands. During the sixteenth century many notable artists were also map makers and several map makers were also artists. 

Dürer-Stabius world map a rare example of Ptolemaeus’ 3rd projection

It became fashionable during the Renaissance for those in power to sponsor and employ those working in the sciences. This patronage also included map makers. On the one hand this meant employing map makes to make maps as status symbols for potentates to display their magnificence. A good example is the map galleries that Egnatio Danti (1536–1586) was commissioned to create in the Palazzo Vecchio in Florence for Cosimo I de’ Medici and in the Vatican for Pope Gregory XIII.

Source: Fiorani The Marvel of Maps p. 110 Note that the map is up side down!

Similarly, Peter Apian ((1495–1552) was commissioned to produce maps for the Holy Roman Emperor, Charles V

Peter Apian cordiform world map 1530 Source: British Library

His son Philipp (1531–1589) did the same for Duke Albrecht V of Bavaria.

Overview of the 24 woodblock prints of Apian’s map of Bavaria

Another example is Oronce Fine (1494–1555), who made maps for Francis I. The first English atlas created by Christopher Saxton (c. 1540–c. 1610) was commissioned by Thomas Seckford, Master of Ordinary on the instructions of William Cecil, 1stBaron Burghley (1520–1598), Queen Elizabeth’s chief advisor.

Saxton England and Wales proof map Source: British Library

These maps came more and more to serve as aids to administration. The latter usage also led to European rulers commissioning maps of their new overseas possessions. 

Another area that required map making was the changes in this period in the pursuit of warfare. Larger armies, the increased use of artillery, and a quasi-professionalisation of the infantry led to demand for maps for manoeuvres during military campaigns. 

Starting around 1500 mapping took off in Renaissance Europe driven by the various factors that I’ve sketched above, a full account would be much more complex and require a book rather than a blog post. The amount of mapmaking increased steadily over the decades and with it the skill of the mapmakers reaching a first high point towards the end of the century in the atlases of Ortelius, De Jode, and Mercator. The seventeenth century saw the establishment of a major European commercial map and globe making industry dominated by the Dutch map makers, particularly the Houses of Blaeu and Hondius.


Filed under Early Scientific Publishing, History of Cartography, History of science, Renaissance Science

Renaissance Science – XVI

In terms of the books rediscovered from antiquity during the Renaissance one of those that had the biggest impact was Ptolemaeus’ Geōgraphikḕ Hyphḗgēsis, which became known in Latin as either the Geographia or Cosmographia. Claudius Ptolemaeus or (Klaúdios Ptolemaîos in Greek) is a scholar, who had a major impart on the development of the mathematical sciences in the second century CE and then again when his writings were rediscovered in the High Middle Ages during the twelfth century translation movement. He wrote important texts on astronomy, astrology, cosmology, harmony (music), and optics, amongst others. However, we know next to nothing about the man himself, neither his date of birth nor his date of death, nor very much else. He lived and worked in the city of Alexandria and people in the Middle Ages made the mistake of thinking he was a member of the Ptolemaic dynasty that ruled Egypt from 323–30 BCE. There is a possibility that he acquired the name because he came from the town of Ptolemaîos Hermaiou in Upper Egypt.

Three of his books the Mathēmatikē Syntaxis (better known in English as the Almagest) on astronomy, the Tetrabiblos or Apotelesmatiká on astrology and the Geōgraphikḕ Hyphḗgēsis on geography form a sort of trilogy. He says in the introduction of the Tetrabiblos that the study of the science of the stars is divided into two parts. The first, his Mathēmatikē Syntaxis, describes where to find the celestial objects and the second, his Tetrabiblos, explains their influence. The Geōgraphikḕ Hyphḗgēsis is in different ways directly related to both books. It is related to the Mathēmatikē Syntaxis in that both works use a latitude/longitude coordinate system to map their respective realms, the sphere of the earth and the sphere of the heavens. This interconnectedness in reflected in the fact that in Early Modern Europe a cosmographer was somebody, who mapped both the celestial and terrestrial spheres. The Geōgraphikḕ Hyphḗgēsis is in three parts, a theoretical introduction on mapping, a gazetteer of the coordinates of a long list of places and, geographical features, and a collection of maps. Like the Mathēmatikē Syntaxis, the Geōgraphikḕ Hyphḗgēsis built on earlier works in the disciple, most notably that of Marinus of Tyre (c. 70–130 CE). To cast a horoscope in Greek astrology, one needs the coordinates of the place for which the horoscope in being cast, the Geōgraphikḕ Hyphḗgēsisdelivered those coordinates. In antiquity the last known reference to the Geōgraphikḕ Hyphḗgēsis was in the work of Cassiodorus (c. 485–c. 585). 

All three of these books by Ptolemaeus were translated into Arabic by the ninth century. Both the Mathēmatikē Syntaxisand the Tetrabiblos had a major impact in Islamic culture, although both were criticised, changed, improved on in wide ranging commentaries by Islamic scholars. It was here that the Mathēmatikē Syntaxis acquired the name Almagestmeaning the greatest to distinguish it from a shorter, less important astronomical text from Ptolemaeus. Geōgraphikḕ Hyphḗgēsis, however had very little impact on Islamic map making being used almost exclusively in an astrological context.

The Mathēmatikē Syntaxis was translated into Latin three times in the twelfth century. Twice from Arabic once by Abd al-Masīḥ of Winchester and once by Gerard of Cremona (1114–1187) and once directly from Greek in Sicily by an unknown translator. These translations establish Ptolemaic astronomy as the de facto medieval European astronomy. In the twelfth century the Tetrabiblos was also translated from Arabic into Latin by Plato of Trivoli in 1138 and directly from Greek into Latin by William of Moerbeke (c. 1220–c. 1286). Integrated into Christian theology by Albertus Magnus and Thomas Aquinas it dominated European astrology right up to the end of the seventeenth century. 

Unlike the Mathēmatikē Syntaxis and the Tetrabiblos the Geōgraphikḕ Hyphḗgēsis was apparently not translated either from Arabic or Greek during the twelfth century. Giacomo or Jacopo d’Angelo of Scarperia better known in Latin as Jacobus Angelus obtained a Greek manuscript, found in Constantinople that he translated, into Latin in about 1406.

Jacobus Angelus’ Latin translation of Ptolemaeus’ Geographia Early 15th century Source via Wikimedia Commons

Here it obtained the title of Geographia or Cosmographia. There is some discussion or even doubt about how genuine the book is, as the oldest known Greek manuscript only dates back to the thirteenth century.

A Byzantine Greek world map according to Ptolemy’s first (conic) projection. From Codex Vaticanus Urbinas Graecus 82, Constantinople c. 1300. Source: Wikimedia Commons

Despite criticism of the quality of Jacobus Angelus’ translation it proved very popular, and the first printed edition appeared in Venice in 1475. However, it contained no maps. A second edition was printed in Rome in 1478, which contained maps printed from copper engravings. The engravings were begun by Konrad Sweynheym (who together with Arnold Pannartz set up the first printing press in Italy) and were completed by Arnold Buckinck after Sweynheym’s death in 1476. The first edition of Geographia with maps printed using woodcuts was published in Ulm in 1482. Three major printed editions in les than a decade indicate the popularity of the book. 

First page of the 1482 Ulm edition go Gepgraphis Source: Wikimedia Commons

The quality, or rather supposed lack of it, of Jacobus Angelus’ translation led to a series of new translations from the Greek. The Nürnberger mathematicus Johannes Werner (1468–1522)

Artist unknown Source: Wikimedia Commons

published a new translation of the theoretical first section, his In Hoc Opere Haec Continentur Nova Translatio Primi Libri Geographicae Cl Ptolomaei, in Nürnberg in 1514.


This in turn was heavily criticised by Willibald Pirckheimer (1470–1530) Nürnberger politician, soldier, humanist scholar and friend and patron of Albrecht Dürer.

Willibald Pirckheimer portrait by Dürer Souce: Wikimedia Commons

Pirckheimer, an excellent classist, published his own translation of the entire text in Nürnberg in 1525.

Claudius Ptolemaeus (Greek, Alexandria (?) A.D. 100?–?170 Alexandria (?)) In Claudii Ptolemaei Geographiacae Enarrationis Libri octo., March 30, 1525 German, Willibald Pirckheimer The Metropolitan Museum of Art, New York, Rogers Fund, 1920 (20.83-) Source
Claudius Ptolemaeus (Greek, Alexandria (?) A.D. 100?–?170 Alexandria (?)) In Claudii Ptolemaei Geographiacae Enarrationis Libri octo., March 30, 1525 German, Willibald Pirckheimer The Metropolitan Museum of Art, New York, Rogers Fund, 1920 (20.83-) Source

Earlier in the fifteenth century another Nürnberger, Regiomontanus (1436–1476), had heavily criticised the Angelus translation. In the catalogue that he published when he set up his scientific printing press in Nürnberg. he announced that he intended to produce and print a new edition of the text, but he died too early to fulfil his intention. Pirckheimer included Regiomonatanus’ criticisms in the introduction to his own new translation of the text.

Pirckheimer’s edition formed the basis for the revised and edited edition published by the cosmographer, Sebastian Münster (1488–1552), in 1540 in Basel. Münster published an updated edition with extra illustrations in 1550. Münster’s Geographia was generally regarded as the standard Latin reference text of the work.

Geographiae Claudii Ptolemaei Alexandrini, Philosophi ac Mathematici praestantissimi, Libri VIII, partim à Bilbaldo Pirckheymero . MÜNSTER, Sebastian (1488-1552), ed. Edité par Basel: Heinrich Petri, March 1552 [colophon], 1552
Geographiae Claudii Ptolemaei Alexandrini, Philosophi ac Mathematici praestantissimi, Libri VIII, partim à Bilbaldo Pirckheymero . MÜNSTER, Sebastian (1488-1552), ed. Edité par Basel: Heinrich Petri, March 1552 [colophon], 1552

The Portuguese mathematicus Pedro Nunes (1502–1578), noted for his contributions to the history of navigation, who was appointed Royal Cosmographer in 1529 and Chief Royal Cosmographer in 1547 by King Joāo III o Piedoso,

Image of Portuguese mathematician Pedro Nunes in Panorama magazine (1843); Lisbon, Portugal. Source: Wikimedia Commons

published his Tratado da sphera com a Theorica do Sol e da Lua in Lisbon in 1537. This was a based on a collection of texts and included the first, theoretical, section of Ptolemaeus’ Geographia. To make it more accessible Nunes published it in Latin, Spanish and Portuguese.

There were, naturally, also other vernacular translations of the work published in the sixteenth century, as for example this description of an Italian translation (borrowed from amateur astronomer and book collector, David Kolb, on Facebook):

Here is another one of the gems from my collection. I proudly present Claudius Ptolemy’s “La Geografia di Claudio Tolomeo Alessandrino” that was published in 1574. This volume is an expanded edition of his treatise on geography. Claudius Ptolemy lived in Alexandria during the 2nd century and is better known by astronomers for his astronomical treatise “The Almagest”. This is the third edition of the Italian translation by Girolamo Ruscelli, which was first printed by Vincenzo Valgrisi in Venice, in 1561. This edition is revised and corrected by Giovanni Malombra. The engraved maps, which are enlarged copies of Giacomo Gastaldi’s maps in his Italian edition of Venice, 1548, are generally the same in the Venice 1561, 1562 (Latin), and 1564 editions printed in Venice. Sixty-three of the maps are printed from the same plates as the 1561 edition. The exceptions are the Ptolemaic world map, “Tavola prima universale antica, di tutta la terra conosciura fin’ a’ tempi di Tolomeo,” which is on a revised conical projection, and the additional map “Territorio di Roma duodecima tavola nuova d’Europa” which is new to this edition. The atlas contains 27 Ptolemaic maps and 38 new maps.

The cosmographer Gerard Mercator (1512–1594), famous for introducing the name atlas for a collection of maps, initially intended to publish a large multi-volume work, which he never completed before he died.

Mercator the Frans Hogenberg portrait of 1574 Source: Wikimedia Commons

The first volume was intended to be his Geographia. In 1578 he published his Tabulae geographicae Cl. Ptolemaei ad mentem auctoris restitutis ac emendatis. (Geographic maps according to Claudius Ptolemy, drawn in the spirit of the author and expanded by Gerard Mercator). This was followed by a second edition in 1584 his Geographiae Libri Octo: recogniti iam et diligenter emendati, containing his revised version of Ptolemaeus’ text.

Geographiae Libri Octo :recogniti iam et diligenter emendati cum tabulis geographicis ad mentem auctoris restitutis ac emendatis ; Cum gratia & Priuilegio Sac Caes. Maiestat. Source:

 I hope I have made clear just how important the rediscovery of the Geōgraphikḕ Hyphḗgēsis was in the fifteenth and sixteenth centuries given the number of editions, of which I have only named a few, and the status of the authors, who produced those editions. In the next episode we will examine its impact on the map making in Europe during this period. 


Filed under Early Scientific Publishing, History of Cartography, Renaissance Science

An eighteenth-century cartographical community in Nürnberg

If you walk up Burgstraße in the city of Nürnberg in the direction of the castle, you will see in front of you the impressive Baroque Fembohaus, which from 1730 to 1852 was the seat of the cartographical publishing house Homännische Erben, that is “Homann’s Heirs” in English. But who was Homann and why was the business named after his heirs?


Fembohaus Source: Wikimedia Commons

Johann Baptist Homann (1664–1724) was born in Öberkammlach in the south of Bavaria. He was initial educated at a Jesuit school and at some point, entered the Dominican Cloister in Würzburg, where he undertook, according to his own account, his “studia humaniora et philosophica.”


Johann Baptists Homann (1664–1725) Portrait by Johann Wilhelm Windter (c. 1696– 1765) Source: Wikimedia Commons

In 1687 he left the cloister moved to Nürnberg and converted to Protestantism. Over the next ten years he vacillated between Catholicism and Protestantism, leaving Nürnberg during the Catholic phases, and returning during the Protestant phases. In 1691 in Nürnberg, he was registered for the first time as a notary public. Around the same time, he started his career as a map engraver. It is not known how or where he learnt this trade, although there are claims that he was entirely self-taught. A map of the district surrounding Nürnberg, produced in 1691/92, shows Homann already as a master in cartographic engraving. From 1693 to 1695 he was in Vienna, then he returned for a time to Nürnberg, leaving again for Erlangen in 1696. Around 1696 to 1697, he was engraving maps in Leipzig.

He appears to have final settled on life as a protestant and permanent residency in Nürnberg in 1698. In 1702 he established a dealership and publishing house for cartography in the city, producing and selling maps, globes, and atlases. His dealership also produced and sold scientific instruments. The field that Homann had chosen to enter was by the beginning of the eighteenth century well established and thriving, with a lot of very powerful competition, in particular from France and Holland. Homann entered the market from a mercantile standpoint rather than a scientific one. He set out to capture the market with high quality products sold more cheaply than the competition, marketing copies of maps rather than originals. In a relatively short time, he had established himself as the dominant cartographical publisher in Germany and also a European market leader.


Planiglobii Terrestris Cum Utroq[ue] Hemisphærio Cælesti Generalis Exhibitio, Nürnberg 1707 Source: Wikimedia Commons

His dealership offered single sheet maps for sale, but he became the first German cartographer to sell atlases on a large scale and is considered the second most important German cartographer after Mercator. His first atlas with forty maps appeared in 1707. This was expanded to the Großen Atlas über die ganze Welt (The Big Atlas of the Entire World), with one hundred and twenty-six maps in 1716.


A fine example of Homann’s 1716 map of Burgundy, one of France’s most important wine regions. Extends to include Lake Geneva in the southwest, Lorraine in the north, Champaigne (Champagne) and Angers to the northwest and Bourgogne to the west. Depicts mountains, forests, castles, and fortifications and features an elaborate title cartouche decorated with cherub winemakers in the bottom right. A fine example of this rare map. Produced by J. H. Homann for inclusion in the Grosser Atlas published in Nuremberg, 1716. Source: Wikimedia Commons

By 1729 it had around one hundred and fifty maps. Johann Baptist’s success was richly acknowledged in his own lifetime. In 1715 he was appointed a member of the Preußischen Akademie der Wissenschaften (The Prussian Academy of Science) and in 1716 he was appointed Imperial Geographer by the Holy Roman Emperor, Karl VI.


A detailed c. 1730 J. B. Homann map of Scandinavia. Depicts both Denmark, Norway, Sweden, Finland and the Baltic states of Livonia, Latvia and Curlandia. The map notes fortified cities, villages, roads, bridges, forests, castles and topography. The elaborate title cartouche in the upper left quadrant features angels supporting a title curtain and a medallion supporting an alternative title in French, Les Trois Covronnes du Nord . Printed in Nuremburg. This map must have been engraved before 1715 when Homann was appointed Geographer to the King. The map does not have the cum privilegio (with privilege; i.e. copyright authority given by the Emperor) as part of the title, however it was included in the c. 1750 Homann Heirs Maior Atlas Scholasticus ex Triginta Sex Generalibus et Specialibus…. as well as in Homann’s Grosser Atlas . Source: Wikimedia Commons

The publishing house continued to grow and prosper until Johann Baptist’s death in 1724, when it was inherited by his son Johann Christian Homann (1703–1730).

Johann Christian studied medicine and philosophy in Halle. He graduated doctor of medicine in 1725, following which he went on a study trip, first returning to Nürnberg in 1729. During his absence the publishing house was managed by Johann Georg Ebersberger (1695–1760) and later together with Johann Christian’s friend from university Johann Michael Franz (1700­–1761).


Hand coloured copper engraving by J. Chr. Homann, showing noth west Africa with the Canary Islands and two large cityviews. Source: Wikimedia Commons

When Johann Christian died in 1730, he willed the business to Ebersberger and Franz, who would continue to run the business under the name Homännische Erben. The publishing house passed down through several generations until Georg Christoph Fembo (1781­–1848) bought both halves of the business in 1804 and 1813. Fembo’s son closed the business in 1852 and in 1876 the entire collection of books, maps, engravings, and drawing were auctioned off, thus destroying a valuable source for the history of German cartography.

Today there is a big market for fictional maps based on fantasy literature such as Lord of the Rings. This is nothing new and Early Modern fiction also featured such fictional maps, for example Thomas More’s Utopia (1516). One very popular medieval myth concerns the Land of Cockaigne, a fictional paradise of pleasure and plenty also known as The Land of Milk and Honey. The German version is Schlaraffenland (literally the Land of the Lazy Apes). The most well-known version of the myth in the seventeenth century was written by Johann Andreas Schneblins (d. 1702) and based on Schneblins’ account of his travels in the utopia of Schlaraffenland Homann produced a map his very popular Accurata Utopiae Tabula.


“Accurata Utopiæ Tabula” (also named “Schlarraffenlandes”) designed by Johann Baptist Homann and printed in 1694 Source: Wikimedia Commons

From the very beginning one distinctive feature of the publishing house was Homann’s active cooperation with other scholars and craftsmen. From the beginning Johann Baptist worked closely with the engraver, art dealer, and publisher Christoph Weigel the Older (1665–1725).


Christoph Weigel, engraved by Bernhard Vogel of a portrait by Johann Kupetzky Source:Wikimedia Commons

Weigel’s most significant publication was his Ständebuch (1698) (difficult to translate but Book of the Trades and Guilds).

Der Pulvermacher Kupferstich Regensburger Ständebuch 1698 Christoph Weigel der Ältere 1654 172

Gunpowder makers, engraving Regensburger Ständebuch, 1698, Christoph Weigel der Ältere (1654, 1725)

Weigel was very successful in his own right but he cooperated very closely with Homann on his map production.

Homann also cooperated closely with the scholar, author, schoolteacher, and textbook writer Johann Hübner (1668–1731).


Johann Hübner, engraving by Johann Kenckel Source: Wikimedia Commons

Together the two men produced school atlases according to Hübner’s pedagogical principles. In 1710 the Kleiner Atlas scholasticus von 18 Charten (Small School Atlas with 18 Maps) was published.


Kleiner Atlas scholasticus von 18 Charten

This was followed in 1719 by the Johann Baptist Homann / Johann Hübner: Atlas methodicus / explorandis juvenum profectibus in studio geographico ad methodum Hubnerianam accommodatus, a Johanne Baptista Homanno, Sacrae Caesareae Majestatis Geographo. Noribergae. Anno MDCCXIX. Methodischer Atlas / das ist, Art und Weise, wie die Jugend in Erlernung der Geographie füglich examiniret werden kann / nach Hübnerischer Lehr-Art eingerichtet von Johann Baptist Homann, Nürnberg, 1719. The title, given here in both Latin and German translates as Methodical Atlas in the manner in which the youth can be reasonably examined in the study of geography according to the pedagogic principles of Hübner, presented by Johann Baptist Homann.


Charte von Europa. Charte von Asia. Charte von Africa. Charte von America. Johanne Baptista Homanno, Norimbergae, 1719 Atlas methodicus / explorandis juvenum profectibus in studio geographico ad methodum Hubnerianam accommodatus

Johann Gottfried Gregorii (1685–1770) was a central figure in the intellectual life of eighteenth-century Germany. A geographer, cartographer, historian, genealogist, and political journalist, he put out a vast number of publications, mostly under the pseudonym Melissantes.


Johann Gottfried Gregorii Source: Wikimedia Commons

In his geographical, cartographical, and historical work he cooperated closely with both Johann Baptist Homann and Christoph Weigel.

 One of the Homann publishing house’s most important cooperation’s was with the Nürnberg astronomer Johann Gabriel Doppelmayr (1677–1750).


Johann Gabriel Doppelmayr Source: Wikimedia Commons

Doppelmayr was professor for mathematics at the Aegidianum, Germany’s first modern high school, and is best known for two publication his Historische Nachricht Von den Nürnbergischen Mathematicis und Künstlern (1730), an invaluable source for historian of science and his celestial atlas, Atlas Novus Coelestis (1742). Doppelmayr had been supplying celestial charts for the Homann atlases but his Atlas Novus Coelestis, which was published by Homännische Erben, contained thirty spectacular colour plates and was a leading celestial atlas in the eighteenth century.


PHÆNOMENA circa quantitatem dierum artificialium et solarium perpetuo mutabilem, ex Hypothesi copernicana deducta, cum aliis tam Veterum quam recentiorum Philosophorum, Systematibus mundi notabilioribus, exhibita – Engraved between 1735 and 1742.

Doppelmayr’s successor as professor of mathematics at the Aegidianum was Georg Moritz Lowitz (1722–1774), who went on to become professor for practical mathematics at the University of Göttingen.


Georg Moriz Lowiz Source: Wikimedia Commons

He worked together with Johann Michael Franz and produced several astronomical publications for the Homännische Erben. Franz as well as being co-manager of the publishing house was also an active geographer, who became professor in Göttingen in 1755. He also published a series of his own books on geographical themes. He sold his share of the publishing house on his younger brother Jacob Heinrich Franz (1713–1769) in 1759.


Johann Michael Franz: Belgium, Luxemburg; Johann Michael Franz – Circulus Burgundicus – 1758

Without any doubt Homann’s most important or significant employee, at least with hindsight, was the cartographer and astronomer Tobias Mayer (1723–1762), who is these days is best known for having calculated the Moon’s orbit accurately enough to make the lunar distance method of determining longitude viable. A self-taught mathematicus he had already published a town plan of Esslingen, two books on mathematics and one on fortifications, when he was appointed to the Homännische Erben in 1746.


Tobias Mayer Source: Wikimedia Commons

It was during his time in Nürnberg that he did his work on lunar astronomy. Like Lowitz, and Franz, Mayer also became a professor in Göttingen, in his case for economics and mathematics.

The three Göttingen professors–Lowitz, Franz, and Mayer–whilst still working for Homann in Nürnberg founded the Cosmographische Gesellschaft (Cosmographical Society), with the aim of improving the standards of cartography and astronomy. Due to lack of funding they never really got their plans of their grounds. Their only products being some propaganda publications for the society written by Franz and one publication from Mayer on his lunar research.


Each of the scholars, briefly sketched here was a leading figure in the intellectual landscape of eighteenth-century Germany and they were all to some extent rivals on the open knowledge market. However, they cooperated rather than competed with each other and in doing so increased the quality of their output.

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Filed under Early Scientific Publishing, History of Astronomy, History of Cartography

The alchemist, who became a cosmographer

As an Englishman brought up on tales, myths and legends of Francis Drake, Walter Raleigh, Admiral Lord Nelson, the invincible Royal Navy and Britannia rules the waves, I tend not to think about the fact that Britain was not always a great seafaring nation. As an island there were, of course, always fisher boats going about their business in the coastal waters and archaeology has shown us that people have been crossing the strip of water between Britain and the continent, as long as the island has been populated. However, British sailors only really began to set out onto the oceans for distant lands in competition to their Iberian brethren during the Early Modern Period. Before the start of these maritime endeavours there was a political movement in England to get those in power to take up the challenge and compete with the Spanish and the Portuguese in acquiring foreign colonies, gold, silver and exotic spices. One, today virtually unknown, man, whose writings played a not insignificant role in this political movement was the alchemist Ricard Eden[1] (c. 1520–1576).

Richard Eden[2] was born into an East Anglian family of cloth merchants and clerics, the son of George Eden a cloth merchant. He studied at Christ’s College Cambridge (1534–1537) and then Queen’s College, where he graduated BA in 1538 and MA in 1544. He studied under Sir Thomas Smith (1533–1577) a leading classicist of the period, who was also politically active and a major supporter of colonialism, which possibly influenced Eden’s own later involvement in the topic.


A c. 19th-century line engraving of Sir Thomas Smith. Source: Wikimedia Commons

Through Smith, Eden was introduced to John Cheke (1514–1557), Roger Ascham (c. 1515–1568) and William Cecil (1520–1598), all of whom were excellent classicists and statesmen. Cecil would go on under Elizabeth I to become the most powerful man in England. From the beginning Eden moved in the highest intellectual and political circles.

After leaving Cambridge Eden was appointed first to a position in the Treasury and then distiller of waters to the royal household, already indicating an interest in and a level of skill in alchemy. Eden probably acquired his interest in alchemy from his influential Cambridge friends, who were all eager advocates of the art. However, he lost the post, probably given to someone else by Somerset following Henry VIII’s death in 1547 and so was searching for a new employer or patron.

Through a chance meeting he became acquainted with the rich landowner Richard Whalley, who shared his interest in alchemy. Whalley provided him with a house for his family and an income, so that he could devote himself to both medicinal and transmutational alchemy. His activities as an alchemist are not of interest here but one aspect of his work for Whalley is relevant, as it marked the beginning of his career as a translator.

Whalley was obviously also interested in mining for metal ores, because he commissioned Eden to translate the whole of Biringuccio’s Pirotechnia into English. Although he denied processing any knowledge of metal ores, Eden accepted the commission and by 1552 he had completed twenty-two chapters, that is to the end of Book 2. Unfortunately, he lent the manuscript to somebody, who failed to return it and so the project was never finished. In fact, there was no English translation of the Pirotechnia before the twentieth century. Later he produced a new faithful translation of the first three chapters dealing with gold, silver and copper ores, only omitting Biringuccio’s attacks on alchemy, for inclusion, as we shall see, in one of his later works.


Title page, De la pirotechnia, 1540, Source: Science History Museum via Wikipedia Commons

In 1552, Eden fell out with Whalley and became a secretary to William Cecil. It is probable the Cecil employed him, as part of his scheme to launch a British challenge to the Iberian dominance in global trade. In his new position Eden now produced a translation of part of Book 5 of Sebastian Münster’s Cosmographia under the title A Treatyse of the New India in 1553. As I explained in an earlier blog post Münster’s Cosmographia was highly influential and one of the biggest selling books of the sixteenth century.


This first cosmographical publication was followed in 1555 by his The Decades of the newe worlde or west India, containing the nauigations and conquests of the Spanyardes… This was a compendium of various translations including those three chapters of Biringuccio, probably figuring that most explorers of the Americas were there to find precious metals. The main parts of this compendium were taken from Pietro Martire d’Anghiera’s De orbe novo decades and Gonzalo Fernández de Oviedo y Valdés’ Natural hystoria de las Indias.


Source: The British Library

Pietro Martire d’Anghiera (1457–1526) was an Italian historian in the service of Spain, who wrote the first accounts of the explorations of Central and South America in a series of letters and reports, which were published together in Latin. His De orbe novo (1530) describes the first contacts between Europeans and Native Americans.


Source: Wikimedia Commons

Gonzalo Fernández de Oviedo y Valdés (1478–1557) was a Spanish colonist, who arrived in the West Indies a few years after Columbus. His Natural hystoria de las Indias (1526) was the first text to introduce Europeans to the hammock, the pineapple and tobacco.


MS page from Oviedo’s La Natural hystoria de las Indias. Written before 1535, this MS page is the earliest known representation of a pineapple Source: Wikimedia Commons

Important as these writings were as propaganda to further an English involvement in the new exploration movement in competition to the Iberian explorers, it was probably Eden’s next translation that was the most important.

As Margaret Schotte has excellently documented in her Sailing School (Johns Hopkins University Press, 2019) this new age of deep-sea exploration and discovery led the authorities in Spain and Portugal to the realisation that an active education and training of navigators was necessary. In 1552 the Spanish Casa de la Contratación established a formal school of navigation with a cátedra de cosmografia (chair of cosmography). This move to a formal instruction in navigation, of course, needed textbooks, which had not existed before. Martín Cortés de Albacar (1510–1582), who had been teaching navigation in Cádiz since 1530, published his Breve compendio de la sphere y de la arte de navegar in Seville in 1551.


Retrato de Martín Cortés, ilustración del Breve compendio de la sphera y de la arte de navegar, Sevilla, 1556. Biblioteca Nacional de España via Wikimedia Commons

In 1558, an English sea captain from Dover, Stephen Borough (1525–1584), who was an early Artic explorer, visited Seville and was admitted to the Casa de la Contratación as an honoured guest, where he learnt all about the latest instruments and the instruction for on going navigators. On his return to England, he took with him a copy of Cortés’ Breve compendio, which he had translated into English by Richard Eden, as The Arte of Navigation in 1561. This was the first English manual of navigation and was immensely popular going through at least six editions in the sixteenth century.


In 1562, Eden became a companion to Jean de Ferrières, Vidame of Chartres, a Huguenot aristocrat, who raised a Protestant army in England to fight in the French religious wars. Eden, who was acknowledged as an excellent linguist, stayed with de Ferrières until 1573 travelling extensively throughout France and Germany. Following the St. Batholomew’s Day massacre, which began in the night of 23–24 August 1572, Eden together with de Ferrières party fled from France arriving in England on 7 September 1573. At de Ferrières request, Elizabeth I admitted Eden to the Poor Knights of Windsor, a charitable organisation for retired soldiers, where he remained until his death in 1576.

After his return to England Eden translated the Dutch musician and astrologer, Jean Taisnier’s Opusculum perpetua memoria dignissimum, de natura magnetis et ejus effectibus, Item de motu continuio, which was a plagiarism of Petrus Peregrinus de Maricourt’s (fl. 1269) Epistola de magnete and a treatise on the fall of bodies by Giambattista Benedetti (1530–1590) into English.


This was published posthumously together with his Arte of Navigation in 1579. His final translation was of Ludovico de Varthema’s (c. 1470–1517) Intinerario a semi-fictional account of his travels in the east. This was published by Richard Willes in The History of Travayle an enlarged version of his Decades of the newe worlde in 1577.

Eden’s translations and publications played a significant role in the intellectual life of England in the sixteenth century and were republished by Richard Hakluyt (1553–1616) in his The Principal Navigations, Voiages, Traffiques and Discoueries of the English Nation (1589, 1598, 1600), another publication intended as propaganda to promote English colonies in America.


Unlike Sebastian Münster or Richard Hakluyt, Eden has been largely forgotten but he made important and significant contributions to the history of cosmography and deserves to be better known.

[1] I want to thank Jenny Rampling, whose book The Experimental Fire, which I reviewed here, made me aware of Richard Eden, although, I have to admit, he turns up, managing to slip by unnoticed in other books that I own and have read.

[2] The biographical details on Eden are mostly taken from the ODNB article. I would like to thank the three wonderful people, who provided me with a pdf of this article literally within seconds of me asking on Twitter

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Filed under Early Scientific Publishing, History of Cartography, History of Navigation

Renaissance Science – V

According to the title, this series is supposed to be about Renaissance science but as we saw in the last episode the Renaissance started off as anything but scientific, so what exactly is Renaissance science, does it even exist, and does it actually have anything to do with the language and linguistics movement that kicked of the period that is now known as the Renaissance? I will start with the second of these questions and return later to the other two.

The history of science in its present form is actually a very young discipline, which really only came to fruition in the twentieth century. There are of course early elements of the discipline scattered around the past but the structured academic discipline as we know it only really began in the decades between the two world wars and came to maturity following the second world war. The early discipline was of course very euro-centric, and a major element was the so-called scientific revolution, which was initially seen as a single historical block. Maria Boas Hall (1919–2009) was, as far as I know, the first to divide that block into two parts, a sort of proto scientific revolution, her The Scientific Renaissance 1450–1630 (published, 1962), followed by the full scientific revolution. She was followed in this bifurcation by Peter Dear in his book Revolutionizing the Sciences: European Knowledge in Transition 1500–1700 (originally 2001, 3rd ed. 2019), who sees two phases, 1500-1600 and 1600-1700. These two books established, I think correctly, the idea of a separate Scientific Renaissance, which preceded the Scientific Revolution.

So, what is the nature of this Renaissance science, how did it differ from the existing medieval science and what changed and when going forward into the so-called scientific revolution? There is quite a lot to unpack here and the first thing we need to do is to stop talking about science and instead talk about knowledge, the more correct translation of the Latin term, scientia used in this period. Also, within the scope of scientia, what we might regard as the areas of hard science, which Aristotle called physics, meaning the study of nature, should more appropriately be referred to as natural philosophy. However, medieval natural philosophy was a very restricted area, it included cosmology but did not for example include astronomy, which was a mathematical discipline. Aristotle rejected mathematics as scientia, because its objects were not real. The mathematical disciplines, such as astronomy and optics, were not regarded as belonging to natural philosophy but were given a sort of halfway status. Natural philosophy also didn’t include any of what we would now call the life sciences.

Knowledge in the European medieval context was divided into two completely distinct areas, which didn’t intersect in anyway. On the one side there was the knowledge propagated by the medieval universities, which, as I explained in an earlier post, was almost totally theoretical book knowledge, with almost no practical aspects to it at all. This knowledge was not static, as it is often falsely presented, but evolved over time. However, this evolution was also a theoretical process. The knowledge progressed through debate and the application of argumentation and logic, not through the acquisition of new empirical facts.

The other area of knowledge was artisanal knowledge, that is the knowledge of the maker, the craftsman. This knowledge was empirical and practical, consisting of directions or instruction on how to complete a given task, how to achieve a given aim or fulfil a given assignment. It might, for example, be how to make bricks out of clay, or how to build a stone arch that would be stable and not collapse under load. This knowledge covered a vast range of activities and had been accumulated from a very wide range of sources over virtually the whole of human existence. This knowledge was, traditional, rarely written down but was usually passed on by word of mouth and direct training from master to apprentice, often from father to son over many generations. This knowledge was in general not viewed as knowledge by scholars within the university system.

Starting around fourteen hundred a process of what we would today call crossover began between these two previously distinct and separate areas of knowledge. Scholars began to write learned works about specific areas of artisanal knowledge, a classic example being Georgius Agricola’s De re metallica, published posthumously in 1556, and craftsmen began to write books explaining and elucidating their forms of knowledge, for example the goldsmith Lorenzo Ghiberti’s I commentarii, which remained unfinished in manuscript and unpublished at the time of his death in 1455. It should be noted that before the Renaissance the people we now call artists were regarded as craftsmen. Crossover is here perhaps the wrong term, as people didn’t just cross the boundary in both directions but the boundary itself began to dissolve producing a meld between the two types of knowledge that would over the next two and a half centuries lead to the modern concept of knowledge or science.

What provoked this move towards practical, empirical knowledge during the Renaissance? There are two major areas of development driving this shift in emphasis, as to what constitutes knowledge. The first is general social, political, economical and cultural developments. The rapid increase in long distant trade produced a demand for new methods of navigation and cartography. Changes in concepts of land ownership also drove developments in cartography and the closely associated surveying. Developments in warfare again drove developments in cartography but also in gunnery, a new discipline, and military tactics in general. The invention of gunpowder and with-it military gunnery drove developments in metallurgy, as did other areas where the use of metals increased, for example in the wider use of metal coinage. The greater demand for metals in turn drove the development of mining. Greater wealth in society in general and the perceived need for rulers to display their power through ostentatious display increased the demand for architecture and fine art. The introduction of gunpowder and gunnery also drove the development of architecture because of the need for better defences. These are just some examples of the growing demand for artisanal knowledge within an increasingly urban culture financed by long distance trade.

But what of the movement that gave the Renaissance its name, which we saw was initially language and linguistic based movement, how did this play a role in this move towards the elevation of the status of empirical and practical knowledge if at all? This is in fact our second area of development. Those early Renaissance scholars, who searched for Latin literature texts and orations in the monastic libraries also unearthed Greek and Latin texts on science, technology, mathematics and medicine and in the general renewal of the culture of antiquity also translated and made these texts available, often arguing for their purity in comparison to the texts from the same authors that had come into Europe through the filter of translation into Arabic and then back into Latin. Example of texts that became available for the first time are Vitruvius’ work on architecture De architectura and Ptolemaeus’ Geographia. The latter had been known to the Islamic cartographers but had not been translated into Latin from Arabic during the twelfth century translation movement. As well as bringing new original Greek and Latin manuscripts into circulation the Renaissance scholars introduced a strong empirical element through their philological work. This work was based on an empirical analysis of various copies of a given work as well as an investigation of the plausibility of a given word, phrase or sentence, which didn’t appear to make sense. Beyond this in some areas the Renaissance scholars, as we shall see in more detail later, began to try and understand what the scholars were referring to in specific instances. For example, which plants was Dioscorides referring to in his De meteria medica? The answer to such questions required real empirical research.

The Renaissance opened up a whole new world of practical, empirical knowledge alongside the theoretical book knowledge of the medieval university. The last question is how did this differ from the knowledge of the following period and when did this transition take place?

The emphasis on this Renaissance empirical knowledge was very much on the practical. How can we use it, where and how can it be applied? During the seventeenth century the emphasis changed to one of devising theoretical explanations for all of the freshly won empirical knowledge from the previous two hundred years. The transition is from how do we use or apply it, to how do we explain it. It is impossible to set a firm date for this transition as it was by its very nature a gradual one, so both Boas Hall and Dear are in a certain sense correct with their respective 1630 and 1600. The transition had definitely already begun by 1600 and probably wasn’t finished, yet by 1630. In my case I follow Francis Yates in choosing the end of the Thirty Year’s War in 1648, as I think the transition had been completed by then at the latest.


Filed under History of Cartography, History of Navigation, History of science, Renaissance Science

Illuminating medieval science


There is a widespread popular vision of the Middle ages, as some sort of black hole of filth, disease, ignorance, brutality, witchcraft and blind devotion to religion. This fairly-tale version of history is actively propagated by authors of popular medieval novels, the film industry and television, it sells well. Within this fantasy the term medieval science is simply an oxymoron, a contradiction in itself, how could there possible be science in a culture of illiterate, dung smeared peasants, fanatical prelates waiting for the apocalypse and haggard, devil worshipping crones muttering curses to their black cats?

Whilst the picture I have just drawn is a deliberate caricature this negative view of the Middle Ages and medieval science is unfortunately not confined to the entertainment industry. We have the following quote from Israeli historian Yuval Harari from his bestselling Sapiens: A Brief History of Humankind (2014), which I demolished in an earlier post.

In 1500, few cities had more than 100,000 inhabitants. Most buildings were constructed of mud, wood and straw; a three-story building was a skyscraper. The streets were rutted dirt tracks, dusty in summer and muddy in winter, plied by pedestrians, horses, goats, chickens and a few carts. The most common urban noises were human and animal voices, along with the occasional hammer and saw. At sunset, the cityscape went black, with only an occasional candle or torch flickering in the gloom.

On medieval science we have the even more ignorant point of view from American polymath and TV star Carl Sagan from his mega selling television series Cosmos, who to quote the Cambridge History of Medieval Science:

In his 1980 book by the same name, a timeline of astronomy from Greek antiquity to the present left between the fifth and the late fifteenth centuries a familiar thousand-year blank labelled as a “poignant lost opportunity for mankind.” 

Of course, the very existence of the Cambridge History of Medieval Science puts a lie to Sagan’s poignant lost opportunity, as do a whole library full of monographs and articles by such eminent historians of science as Edward Grant, John Murdoch, Michael Shank, David Lindberg, Alistair Crombie and many others.

However, these historians write mainly for academics and not for the general public, what is needed is books on medieval science written specifically for the educated layman; there are already a few such books on the market, and they have now been joined by Seb Falk’s truly excellent The Light Ages: The Surprising Story of Medieval Science.[1]  


How does one go about writing a semi-popular history of medieval science? Falk does so by telling the life story of John of Westwyk an obscure fourteenth century Benedictine monk from Hertfordshire, who was an astronomer and instrument maker. However, John of Westwyk really is obscure and we have very few details of his life, so how does Falk tell his life story. The clue, and this is Falk’s masterstroke, is context. We get an elaborate, detailed account of the context and circumstances of John’s life and thereby a very broad introduction to all aspects of fourteenth century European life and its science.

We follow John from the agricultural village of Westwyk to the Abbey of St Albans, where he spent the early part of his life as a monk. We accompany some of his fellow monks to study at the University of Oxford, whether John studied with them is not known.


Gloucester College was the Benedictine College at Oxford where the monks of St Albans studied

We trudge all the way up to Tynemouth on the wild North Sea coast of Northumbria, the site of daughter cell of the great St Alban’s Abbey, main seat of Benedictines in England. We follow John when he takes up the cross and goes on a crusade. Throughout all of his wanderings we meet up with the science of the period, John himself was an astronomer and instrument maker.

Falk is a great narrator and his descriptive passages, whilst historically accurate and correct,[2] read like a well written novel pulling the reader along through the world of the fourteenth century. However, Falk is also a teacher and when he introduces a new scientific instrument or set of astronomical tables, he doesn’t just simply describe them, he teachers the reader in detail how to construct, read, use them. His great skill is just at the point when you think your brain is going to bail out, through mathematical overload, he changes back to a wonderfully lyrical description of a landscape or a building. The balance between the two aspects of the book is as near perfect as possible. It entertains, informs and educates in equal measures on a very high level.

Along the way we learn about medieval astronomy, astrology, mathematics, medicine, cartography, time keeping, instrument making and more. The book is particularly rich on the time keeping and the instruments, as the Abbott of St Albans during John’s time was Richard of Wallingford one of England’s great medieval scientists, who was responsible for the design and construction of one of the greatest medieval church clocks and with his Albion (the all in one) one of the most sophisticated astronomical instruments of all time. Falk’ introduction to and description of both in first class.


The book is elegantly present with an attractive typeface and is well illustrated with grey in grey prints and a selection of colour ones. There are extensive, informative endnotes and a good index. If somebody reads this book as an introduction to medieval science there is a strong chance that their next question will be, what do I read next. Falk gives a detailed answer to this question. There is an extensive section at the end of the book entitled Further Reading, which gives a section by section detailed annotated reading list for each aspect of the book.

Seb Falk has written a brilliant introduction to the history of medieval science. This book is an instant classic and future generations of schoolkids, students and interested laypeople when talking about medieval science will simply refer to the Falk as a standard introduction to the topic. If you are interested in the history of medieval science or the history of science in general, acquire a copy of Seb Falk’s masterpiece, I guarantee you won’t regret it.

[1] American edition: Seb Falk, The Light Ages: The Surprising Story of Medieval Science, W. W. Norton & Co., New York % London, 2020

British Edition: Seb Falk, The Light Ages: A Medieval Journey of Discover, Allen Lane, London, 2020

[2] Disclosure: I had the pleasure and privilege of reading the whole first draft of the book in manuscript to check it for errors, that is historical errors not grammatical or orthographical ones, although I did point those out when I stumbled over them.


Filed under History of Astrology, History of Astronomy, History of Cartography, History of Mathematics, History of Navigation, History of science, Mediaeval Science, Myths of Science