Doodle réalisé le 5 mars 2015 à l’occasion 503^e anniversaire de la naissance de Gérard Mercator. © Google.com

Apart from the very first globes he made for Chancellor Nicholas de Granvelle (the terrestrial model, in 1541) and Bishop George of Austria (the celestial model, in 1551), and the numerous ones commissioned by Joachim Camerarius for the Frankfurt fairs and by the printer Christophe Plantin in Antwerp, Mercator no doubt sold other pairs to the University of Leuven, Duisburg Gymnasium and various schools in Belgium and Germany, as well as to abbeys, convents and individuals interested in the sciences.

It is not known how many globes were printed and assembled altogether. Since they were never copied or updated, they gradually became obsolete as new geographical discoveries were made in the second half of the 16th century. Production eventually ceased.

At present fewer than 30 documented copies still exist, along with a set of printed paper gores. Either in pairs or singly, nearly all these globes are located in Europe. A scarce few can be found in the US and Japan. The largest numbers are in Germany and Austria, followed by the UK, Belgium, France, Italy, the Netherlands, Poland, Sweden and Switzerland. All belong to public institutions such as museums, monasteries, observatories or universities. There is no known private market for these artefacts.

To support his growing family, Gerardus Mercator became a manufacturer of scientific instruments and a designer, engraver and illuminator of maps. Around the year 1537, he created a representation of the Earth and the Heavens, which he first drew on paper and then reproduced on copper before finally printing and illuminating it. Using this same method, he made maps and globes which he designed and engraved himself. He was the only mapmaker of his time who mastered the entire production chain, from the theoretical conception of a work to its practical realisation. No other maps or globes of the period are comparable to his.

Nicholas Perrenot (1486-1550)

Antoine Perrenot (1517-1586)

Christophe Plantin (1520-1589)

Joachim Camerarius the Younger (1534-1598)

A key turning point came when he met the father of his friend Antoine Perrenot. Nicholas Perrenot (1486-1550), lord of Granvelle in Franche-Comté, became a shrewd, influential and devoted go-between in the court of Emperor Charles V as his chancellor and trusted adviser. In 1541 Mercator dedicated his terrestrial globe to him, the first of a large series that would ensure Mercator’s livelihood.

Accused of entertaining Reformist ideas, Mercator was imprisoned from 1544 to 1545. After his release he left Leuven and moved to Duisburg, where he developed his maps and globes business with the help of his sons, grandsons and a number of workers. It is known that his globes were in such demand that he could not keep up with his order book. Matched pairs of his globes were sold for 24 guilders at first and went on to fetch 36 to 45 guilders. Middlemen helped the family enterprise by buying globes and finding their own customers for them. The profiles of two of these middlemen are particularly well documented :

• Christophe Plantin (c. 1520-1589), a renowned printer, publisher and binder in Antwerp, is said to have bought 25 pairs of globes from Mercator.
• Joachim Camerarius the Younger (1534-1598), a physician from Nuremberg, was one of Mercator’s best customers, acting as middleman by buying several copies each year which he shipped up the Rhine and the Main to Cologne and beyond to Frankfurt, where they could be sold at the two annual fairs.

Initially globes were solid spheres made by hand from a variety of materials such as marble, glass, wood or metal. Later they became hollow spheres consisting of thin sheets of metal including copper. Obviously, these were single copies. The advent of the printing press in the mid-15th century made it possible to produce globes more cheaply in limited series. In this case they were made starting from wood or copper engravings printed on paper gores, which was then cut out and pasted onto the sphere.

The assembly of a printed globe began by making a hollow sphere separated into two hemispheres composed of cellulosic material such as papier mâché or cloth pasted in successive layers. The two hemispheres were joined and mounted on a central shaft, allowing the sphere to rotate. However, because the weight was seldom evenly distributed, globes were usually out of kilter. To balance them on their axis, little pockets of copper or sand were sometimes placed inside, thus preventing them from sagging in a particular spot. The printed gores were then cut out and pasted on the sphere. Such globes were fragile and difficult to transport.

In the 16th century, Flanders and the Low Countries became important intellectual and scientific centres where intaglio printing flourished. Thus, all the ingredients were combined for Gerardus Mercator to be able to produce top-quality printed globes. Though destined for the upper classes, these gradually made it possible to disseminate knowledge to a wider public.

From 1500 to 1830 printed globes were always produced and exhibited in matched pairs, one celestial and the other terrestrial. Together they symbolised the universe of knowledge and knowledge of the Universe. By portraying the Earth and the Cosmos as identical size, they moreover conveyed a different relationship in which the Earth became an object in itself, capable of being thought about independently, no longer subordinated to the heavens above. Nor did this vision encompass only the oecumene (inhabited land) and instead provided a broader geographical perspective. From 1830 terrestrial globes little by little developed a solo career whereas celestial globes were increasingly regarded as curios and fell by the wayside before finally being replaced by the modern-day planetarium.

So printed globes, produced and distributed quickly in series of varying size, became the standard. Surprisingly, the methods used to craft them, set out very clearly by Gerardus Mercator, have barely changed since the mid-16th century.

The astronomer and geographer Claudius Ptolemy (c. 90-168) spent his life in Alexandria, the main centre of scientific learning of the time. One could say that he was at once the last great cartographer and astronomer of Antiquity and the first of the Western world. A master compiler, he owes much of his reputation to the fact that nearly all his work was conserved by Arab scholars and then translated into Latin.

His most famous work is a treatise on astronomy divided into thirteen books known by the title Almageste. In it Ptolemy professed a geometric conception inherited from Hipparchus (c. 190-120 BC), which placed the Earth as a sphere at the centre of the universe. This conception would leave astronomy at a standstill until the advent of observational instruments and the proposal of a heliocentric system by Copernicus (1543), Galileo (1630) and Kepler. The Almageste also contained a catalogue of 1022 stars and 48 constellations that Mercator would use for his celestial globe.

Ptolemy’s second work, Geography, was concerned with describing the Earth. It is not known whether it was an original treatise or a vulgarisation. In it Ptolemy explained that geography had to faithfully project the reality of the physical world using maps. The work was also a sort of cartographic glossary of known places and their locations.

The first printed copy of Ptolemy’s Geography containing maps, published in 1477, summarised the state of geographical knowledge around the year 125. For Renaissance scientists it provided an introduction to mathematical cartography, to the use of cartographic projections, to latitudes and longitudes as a grid for maps’ content and to new factual knowledge about geography. The work contained a very famous map of the world easily suggesting that by sailing towards the west one could reach the Orient. This representation was reproduced with its errors until the 17th century.

Ptolemy’s works were both a fillip and a muddle for cartography as a science. By depicting the Earth as a sphere, they sparked a search for a way to project this spherical shape onto a plane. By pointing up the need to determine the locations of places in relation to the equator and a prime meridian, they would provide an impetus to mapmakers. But by passing down the imprecisions of geography as it stood at the end of Antiquity into maritime mapmaking, a field that although still empirical was nevertheless much closer to reality, Ptolemy’s conception obscured the truth.

While the oldest surviving celestial map was drawn by Dunhuang (649-684) in China, we must refer to Greek science to retrace Western history’s spherical representations of the heavens.

Using a globe to model the geometry of the heavens was essential to Greek astronomy, where this spherical representation took hold from the 4th century BC. Most of these globes depicted the constellations in allegorical form with their main stars and a number of circles such as the meridians, the equator and the ecliptic.

In his Syntaxis mathematica, better known by the title Almagest, Ptolemy (2nd century AD) analysed the various components of the Earth-Heavens system geometrically. He also discussed the construction of celestial globes, listing 48 constellations, the ecliptic coordinates of 1022 stars and their size (which he called “magnitude”). With few improvements this breakdown of the heavens held sway for many centuries, including into the 1500s.

Arab science preserved the fundamentals of Greek astronomy from 900 to 1300 AD. The knowledge of stereoscopic projection, used in astrolabes, was thus handed down to the Western Latin world around the year 1000 via Muslim Spain. A dozen celestial globes, made of brass and produced in the Arab world during the Middle Ages, are currently known to exist.

In the Christian world, representing the vault of heaven on a globe became a popular way of telling time. This was mainly useful for planning religious celebrations including Easter. Small wonder then that the first celestial globes in western Europe were to be found in monasteries. They are extremely rare, however, as they were single copies carved out of wood.

One of the first celestial maps in the Western world was the Vienna Manuscript, an anonymous work produced around 1440 and currently conserved by the Austrian National Library. This map represented an important step in the development of mathematical cartography in Europe. For the first time, the human figures embodying constellations are drawn from the back.

Representations of the Cosmos emerged in earnest during the Renaissance. Scientists in this period began to demystify the heavens by breaking away from medieval mythologies and establishing a new tradition based on mathematics. Albrecht Dürer (1471-1528), Conrad Heinfogel († 1517) and Johann Stabius (c. 1460-1522) produced the first printed star maps, no doubt inspired by the Vienna Manuscript.

These maps were followed in 1515 by the first printed celestial globe. Made in Nuremberg by Johann Schöner, it was 27 cm in diameter and covered with gores printed from wood engravings. This globe, part of a matched pair with the terrestrial one, seems to have served as a model for the one in The Ambassadors, a 1533 painting by Holbein the Younger.

In 1537 the mathematician, astronomer, physician and geographer Gemma Frisius produced a globe in Leuven, this time using copper plates, which represented a significant step forward in globemaking. Frisius referred to himself on his work as a medicus ac mathematicus, a designation explaining how it integrated medicine and astrology, two fields that were then linked by a macrocosmic and microcosmic vision of the elements and the “humours”.

While drawing on Dürer’s work, Frisius improved the representation of the Cosmos by adding numerous details: the tip of Eridanus was probably inspired by the German mathematician Peter Apian (1495-1552); the precession of the equinoxes (19°40’) was identical to Dürer’s; the magnitudes of stars were better designated; and a number of star names were added. The globe also featured references to astrological relationships between stars and planets, for example by associating Venus and Mercury with Spica or Saturn and Mars with Aires.

In 1551 Mercator followed the example of his master Frisius and matched his own terrestrial globe with a celestial one 41 cm in diameter. The pair marked a major milestone and, establishing Mercator as the father of modern globemaking.

Human awareness of time and space arose in the distant past, before the dawn of history. The sun, the moon and the stars, serving as both clock and calendar, gradually provided points of reference for travelling, sailing and planting crops. Historically, celestial representations preceded terrestrial ones. Modern societies’ idea of making models of the Cosmos and the Earth based on the laws of geometry was, to a large extent, a legacy of the ancient Greeks.

From the 4th century BC the ancient Greeks represented the celestial vault as a sphere. References can also be found to terrestrial globes made, for example, by Eudoxus of Cnidus (c. 276-194 BC) and Crates of Mallus (c. 220-140 BC). The image of the Cosmos changed little after Antiquity, but for the image of the Earth it would be a different story.

In ancient Greece it was writings that mattered. Those of Hesiod (8th century BC) and Homer (8th century BC?), with the Iliad and the Odyssey, are indicative of that mythical time when the world was a narrative ensemble.

The classical Greek period gave rise to measurement. Geometry developed gradually. Thales of Millet (c. 625-547 BC) envisaged the Earth as a sphere and Anaximander of Millet (c. 610-546 BC) revealed for the first time that the Earth was a heavenly body.

Finally, during the Greco-Roman period, pragmatism and science gained the upper hand. The Earth became a territory. Eratosthenes of Cyrene (c. 276-194 BC) was the first to measure its circumference while Ptolemy of Alexandria (c. 90-168) would sum up this store of Greek knowledge in the 2nd century AD. The advance of cartography in the 16th century owed much to ancient scientific works via their translation into Latin and availability in print, particularly the works of Ptolemy. His Geographia, a roundup of the knowledge of world geography inspired by Marinos of Tyre, was published with maps for the first time around 1477. The Almagest, his monumental work on astronomy, imposed a geometric vision that would long be regarded as the standard model of the universe, until the idea of a heliocentric view was proposed.

The expansion of known space during the Age of Discovery, from the mid-15th to the late 16th century, enabling Europeans to apprehend the world as an entirety and to recognise all the Earth’s territories that could be reached by sea. The historian Pierre Chaunu called this view the “désenclavement planétaire”, or end of global isolation, which marked the start of modernity.

The acceleration of geographical discoveries and the development of navigation created a crucial need for innovations and state-of-the-art instruments to ply the world, measure it and represent it. From 1450 the advent of the printing press made it possible to circulate texts and translations of ancient scientific documents in large numbers. The Renaissance forged ahead, paving the way for new ways of seeing and hypothesising the world. Gerardus Mercator embodies this spirit of invention in the field of cartography.

Intellect and pragmatism

On the face of it, two major influences marked cartography during the Renaissance, one intellectual and the other pragmatic. These two tendencies would coexist, interpenetrate or collide. The work of the Greek scientist Claudius Ptolemy, regarded as the leading light until the Renaissance, was repeatedly called into question in the wake of new discoveries and the accounts of the great mariners.

Geographic frontiers had been rolled back considerably since Marco Polo in the 13th century and Portugal’s explorations in the 15th century. After the first circumnavigation of the Earth by Ferdinand Magellan and his crew, in 1522, the outlines of the main continents were nearly sketched.

New maps were appearing year after year, capturing mankind’s burgeoning knowledge of the Earth. Fresh discoveries were added; for regions they still lacked information about, cartographers referred to the accounts of explorers and Ptolemy’s Geography.