The World of Gerard Mercator: The Mapmaker Who Revolutionised Geography

By the time Mercator was born, the printing press had made books readily available across Europe, but the language of religion and intellectual debate was the same as it had been in the days of the medieval copyists toiling over manuscripts in the monasteries. Not just the Bible but also scientific, medical, and philosophical texts were written in Latin. At the University of Leuven and later in Duisburg, Mercator’s conversation and correspondence were also in Latin. However, by 1594, the year he died, Bibles in the daily language of the people were commonplace. Galileo’s writings appeared in clear and lucid Italian. This signified more than a change of vocabulary or language; scientists, by the turn of the century, were gaining the confidence to rely on observation, measurement, and reasoning rather than looking into the past for inspiration.

Gerard Mercator

Science Photo Library, London

Mercator’s own life reflected the era of change in which he lived, being full of apparent contradictions and opportunism, and extending over one of civilization’s major crossroads. In many ways a child of the past, he was born into poverty and owed his first chances in life to the wealth of the traditional Catholic Church; yet his surviving letters are those of a tolerant reformist with Protestant leanings, who kept his religious views to himself. Like the artists of the Italian Renaissance, he relied on the favor of princes, dukes, and high dignitaries of the Church, but he also built a commercial business which depended on the new prosperous middle class that economic growth had created.

Mercator studied and created maps with a passionate attention to detail that would have been familiar to any of the scholars or artists of the Italian Renaissance. In his studies, he showed unswerving respect for the authority of Claudius Ptolemy of ancient Alexandria, who had proposed his own map projections – ways in which the Earth might be flattened out onto a sheet of paper. At the same time, Mercator did more than any other geographer of his day to demonstrate that Ptolemy’s classical ideas of the world were outdated, misleading, and often simply wrong. As a cartographer, Mercator spent his lifetime collecting, collating, and assessing the latest reports from explorers whose discoveries rendered Ptolemy’s ideas inadequate to describe the new world that was emerging; as a mathematician, he answered the problem of projection with his own solution, which has lasted for more than four hundred years.

There are few reliable contemporary descriptions of Mercator, few clues to the personality of the scholar who did more than anyone in the last two thousand years to turn mapmaking into a precise science. Moreover, many of his letters are lost. A number of the letters that do survive are appeals to dukes and princes of the German city-states, to dignitaries of the Catholic Church, even to the Holy Roman Emperor Charles V himself for support and sponsorship, for Mercator well understood the advantages of influential backing. Throughout his life, he was a driven man: Long hours at his desk as a student gave way to long hours at his workbench as he built the business that was to make his fortune, and the habit of study never left him. In the infirm years before his death, he would urge his children to carry him, chair and all, to his books.

Fear is an overpowering emotion in those of his letters that do survive – fear of death and damnation, fear of not completing the work he had begun, fear of failure. Orphaned at an early age, sent off to the harsh rigors of a monastic school, he knew little of maternal love or family stability, and his difficult childhood left him cautious and circumspect. In his business life, he was assiduous in appealing for official copyright protection for his maps and globes, and the careful investment of his profits in property and forestland showed his awareness of the importance of security.

He was also aware, as he had to be, of the value of silence. In the religious conflicts of his time, his principles were those of a reformer, but his arrest and imprisonment at the hands of the Inquisition clearly reinforced his instinct for caution. Even after he moved from Leuven to the more relaxed environment of Duisburg, in Germany, he avoided any involvement in religious argument. Rather than the perils of theological disputation, he enjoyed his reputation in the town as a good host and dinner guest. The handful of contemporary accounts speak of him as a witty and entertaining conversationalist, and gifts of food and wine from the city authorities suggest a man who was known to enjoy good company and a well-stocked table.

But more than anything else, he was a scholar. Though he never traveled beyond the well-known towns of northern Europe, never, so far as we know, even boarded a ship, his work, together with that of sea captains and explorers, allowed people of the sixteenth century and the generations who followed them accurately to imagine the world beyond the horizon.

He created his projection almost in passing and showed few signs of appreciating the importance of what he had done – and yet it has defined the shape of the world in the modern age. There is no doubt that it produced a distorted image, as any flat map of the spherical world must. As a result, Mercator himself has often been accused in the last few years of racism, because his projection makes the continent of Africa seem smaller than it really is, or of imperialism, because it appears to exaggerate the size and importance of Europe – accusations that a scholar of the sixteenth century would not even have understood. The challenge of spreading the globe out flat on a desk, of presenting the known world in a way that could readily be seen and comprehended, was one with which philosophers, travelers, and geographers had been struggling for thousands of years. By Mercator’s day, the time was ripe for a solution.

Chapter One Pushing Back Shadows (#ulink_8ed32436-0fff-5178-ae8a-532354a7f5dd)

MERCATOR WAS BORN barely twenty years after Christopher Columbus first crossed the Atlantic. Yet even though the fifteenth and sixteenth centuries are considered the great age of discoveries, an astonishing amount was known, or at least rumored, about North, South, East, and West before any of the memorable voyages of exploration ever left port.

Nearly two thousand years earlier, the Greek historian Herodotus was told of Phoenician sailors who claimed to have sailed around the southern tip of Africa.* (#litres_trial_promo) A hundred years or so after his death, during the fourth century BC, another Greek explorer, Pytheas of Massilia, sailed into the far northern seas, to a country he called Thule, where he said the Sun went to sleep.† (#litres_trial_promo) Still farther north, he said, land, sea, and air coalesced into a mixture on which people could neither walk nor sail. Ancient Norse sagas spoke of journeys to “a new land, extremely fertile and even having vines” that lay far to the west, beyond the setting Sun.

Claudius Ptolemy, the Alexandrian librarian and scholar of the first century AD, had heard about the island of Taprobane, or modern Sri Lanka.

Commercial ambition drove travelers on over new horizons. From as early as 500 BC, trading caravans from China made their way along a variety of routes through central Asia, bringing bales of fine silk to be bartered for Persian warhorses or Arabian spices, frankincense, and myrrh. Lines of heavily laden camels followed secret and well-guarded tracks through the deserts of Arabia, carrying gold, ivory, rare woods, and the spices of Yemen to the trading centers of the Mediterranean. Elsewhere, Phoenician ships journeyed beyond the Pillars of Hercules at the mouth of the Mediterranean to the very edges of the known world, bringing back tin from the Scilly Isles off the southwest coast of Britain. The prophet Ezekiel described the goods carried by the Phoenician traders, and the towns to which they traveled. “Tarshish was thy merchant, by reason of the multitude of all kind of riches, with silver, iron, tin, and lead, they traded in thy fairs. Javan, Tubal, and Meshech, they were thy merchants: they traded the persons of men and vessels of brass in thy market. They of the house of Togarmah traded in thy fairs with horses and horsemen and mules.”

The Phoenician capital Tyre, on the coast of what is now Lebanon, had trading links that extended through the entire eastern Mediterranean and far beyond. The places Ezekiel named in these verses as the Phoenicians’ trading partners in the sixth century BC were in central Asia, southern Arabia, Armenia, and the coast of Spain, and his list of the merchandise – slaves, animals, manufactures, luxuries, and other goods – that appeared in their marketplaces lasted for more than twenty biblical verses. Travel and its commercial benefits were common enough; from the earliest times, explorers and adventurers had returned with exotic cargoes, but the stories they brought back were confused and unreliable. The island of Taprobane that Ptolemy described was said to dwarf the Indian peninsula that lay to its north, while the great medieval map of the world, dating from the late thirteenth century and still on display at Hereford in England, shows two distinct Niles, one running into the eastern Mediterranean, the other snaking across almost the whole width of the African continent. The accounts of the early adventurers were neither more nor less believable than the grotesque creatures with which ancient Greek and Roman authors loved to people the unknown places. There was no agreed view of the world; anything was possible. Travelers had no reliable or accurate way to record what they had found, to set it out for people to see. To become part of a shared image of the world, their stories had to be written down, described, and mapped.

Today, the oldest so-called maps look like little more than a few carved scratches, their meaning lost with the civilizations that created them. About four thousand years ago, craftsmen near the present-day village of Bedolina, some ten thousand feet high in the Italian Alps, set about carving the rock with rough bronze or iron tools. They drew pictures of animals, daggers, and suns, much as their cavemen ancestors elsewhere in Europe had done ten thousand years earlier. But the artists of Bedolina also produced one of the first known maps. The Mappa di Bedolina is approximately four yards wide and six yards high, an ambitious patchwork of carved lines and symbols, with a series of crudely drawn rectangles, most of them filled with carefully spaced dots and linked with snaking irregular lines. They seem to represent fields with paths, rivers, or irrigation canals running between them – a graphic illustration of a cultivated landscape in the Valley of Valcamonica below. Their carvings could have had some religious or magical purpose, but after four millennia, we can only guess at what it might have been. Armed figures, huts, and shapes like ladders were added to the map hundreds of years afterward, maybe adapting it for new mystical or ceremonial rites in a mixture of religious faith and straightforward observation that was to characterize mapmaking through the ages.

The Mappa di Bedolina in Italy.

Centuries later, merchants and travelers who were pushing farther and farther afield in the search for new markets brought back garbled reports of the mighty Rivers Don and Nile running south out of Asia and north out of Africa to form a T-shape with the well-traveled waters of the Mediterranean. The waters of the ocean were then thought to surround the world in a gigantic O, leading to the creation of the so-called T-O maps, which represented for ancient Greek, Roman, and even Arab seamen an agreed image of the outline of the world.

A T-O map from Etymologiarum by Isidore of Seville

British Library, London, Rare Books and Maps Collections

THAT WAS THE WORLDVIEW Claudius Ptolemy inherited as he worked in the great library of Alexandria around the middle of the second century AD. His name appropriately linked the Greek-Egyptian Ptolemy with the Latin Claudius, for Alexandria was a cosmopolitan place, more than five hundred miles from Greece, under Roman rule, and yet at the heart of Greek civilization. The city, with its port and its great lighthouse, was a triumphal expression of Greek civilization and Roman power. Like Antwerp in Mercator’s day, it was one of the world’s great cultural and commercial crossroads, with mineral ores and spices ferried down the Nile from the depths of Africa and along an elaborate network of canals, then traded along the waterfront with the day-to-day cargoes that had been brought into harbor from the busy eastern Mediterranean. Sailors and merchants brought with them tales of distant lands like Taprobane, half-digested stories that might conceal a thin vein of truth for scholars trying to extend their grasp of the unknown world. Busy ports have always been the mines of geographers; travelers’ gossip was the unsmelted ore of exploration for Ptolemy, as it was to be for Mercator.

The merchants brought wealth to Alexandria as well. In the days of its greatness, the story went, the buildings contained so much glistening marble that a tailor could thread his needle by the reflected light of the Moon. The library where Ptolemy worked, with its collection of some seven hundred thousand manuscripts in Hebrew, Greek, and Egyptian, was one of the most obvious expressions of that wealth. Just as the merchants in the port haggled and bargained over the commerce of the mightiest empire the world had ever seen, so Alexandria’s scholars swapped ideas and theories in the library and the museum associated with it.

There are no surviving original manuscripts of Ptolemy’s work, and hardly any facts known about his life, but it would be hard to exaggerate the effect of his books on the generations that followed him. For centuries after his death, they were largely forgotten in the West, but to Mercator, the writings of Ptolemy represented the fount of ancient knowledge, the standard by which new discoveries and theories should be measured. Apart from the eight books of the Geographia, the Almagest set out Ptolemy’s views on astronomy and the place of the Earth at the center of the universe, while his various other writings encompassed mathematics, music, and history.

Other writers had concentrated on stories of the wonders that lay at the farthest reaches of knowledge, but Ptolemy’s main interest lay in establishing a reliable and coherent system for showing the spherical Earth on a flat sheet of paper. Philosophers could only suggest what form the Earth took, while travelers either by land or by sea could do little more than estimate distances – in both cases, their contributions were merely elegant guesswork. The generally accepted image of the land surrounded and limited by the ebbing and flowing waters of the sea suggested a comfortingly finite world. Ptolemy raised the possibility of a world beyond those boundaries, basing his conclusions not just on the arguments of the philosophers and on the reports of travelers but also on exact astronomical measurements.

Ptolemy saw geography as a mathematical enterprise, a matter of measurement and calculation rather than the simple telling of stories. Like Mercator some fourteen centuries after him, he designed and made instruments for measuring angles and altitudes in the heavens; his Geographia includes descriptions of a brass astrolabe and a quadrant for calculating the height of the Sun in the sky.

Ptolemy knew the true location of a place could be fixed by taking precise sightings of the stars. The Geographia therefore included a catalog of some eight thousand place-names, rivers, mountains, and peninsulas, each of them with its position defined by degrees of latitude and longitude. It is a work of staggering ambition and exactitude – the first time anyone had attempted to use coordinates in such a precise way. Many of the observations Ptolemy needed to make the calculations had already been taken, but to place cities in remote or unexplored parts of the world, he had no choice but to rely on traditional accounts and the estimates of travelers. In such a case, he said, the mapmaker should use his judgment as to what figures to use, “deciding what is credible and what is incredible.”

It is impossible to know whether Ptolemy drew any maps to go with his Geographia. The illustrations that adorned medieval versions of his books were additions by later copyists working to his descriptions and coordinates, but in them his worldview, with the traditional three continents of Europe, Asia, and part of Africa, can clearly be recognized. Taprobane is grotesquely out of proportion in comparison with the half-formed India that lies to its north, and the coastline of the Far East is clearly drawn largely from imagination, but the Arabian peninsula and the whole of the Mediterranean basin are presented in some detail.

Perhaps most important of all, though, Ptolemy left open the possibility that there were more lands to be discovered beyond the extent of his own knowledge. Where the Romans and Greeks who came before him had been content to keep their studies inside the limits of the habitable world, his interest was in the Earth as a whole, and geography, for him, was no more or less than the art of making maps. “It is the prerogative of Geography,” he said, “to show the known habitable earth as a unit in itself, how it is situated and what is its nature; and it deals with those features likely to be mentioned in a general description of the earth, such as larger towns and great cities, the mountain ranges and the principal rivers.”

The circle of seas that surrounded the Earth in the early T-O maps was one way of suggesting a round world, but Ptolemy’s was the first serious attempt to deal with the problem of projection. He described two possible solutions, based on a simple rectangular grid that ancient Greek philosophers had already devised, but adapting it to take account of the fact that the Earth was curved, not flat.* (#litres_trial_promo) The systems he suggested were, as they had to be, a compromise, and one which worked satisfactorily enough within the limits of the known world. Even in the sixteenth century, most maps were still produced on grids that were simple adaptations of Ptolemy’s projections. Mercator’s greatest achievement would lie in rethinking these fifteen-hundred-year-old proposals.

Ptolemy’s geographic writings are filled with errors of fact, many of them, as he engagingly admitted himself, due to a lack of basic information. Some, such as the “great southern continent” that he believed must balance the world on its axis, would endure, like the fabulous creatures described by Herodotus and other Greek writers, for centuries after Mercator.

For all its shortcomings, though, the rediscovery and publication of the Geographia in the West laid the foundations for the work of the great cartographers of the sixteenth century. The book traveled with Columbus to the New World; when Mercator compiled his great world map of 1569, he began with Ptolemy’s calculation of the position of Alexandria. The Geographia was still being treated as the ultimate authority fourteen hundred years after its author’s death. It shows a man trying to apply scientific methods to achieve a precise, objective representation of the world in a way that was unique in his time, and remained so until Mercator’s day.

IN THE EAST, the scanty records and remains of the work of the Chinese suggest that they had their own impressive tradition. Around the third century AD, a government minister of works named Phei Hsiu set out official principles for the making of maps under the Chin Dynasty. The most important of these was that they should be constructed on a rectangular grid in order to create a consistent scale and locate places accurately. There is no evidence that Ptolemy’s thinking had reached the Far East – a grid system had been introduced in China some two hundred years before Phei Hsiu by Ptolemy’s near-contemporary Chang Heng, an astronomer royal of the Han Dynasty.* (#litres_trial_promo) He wrote of a spherical world suspended in infinity, like a yolk in an egg, and the system he introduced of building up a map by equal squares – “casting a net over the Earth,” in a contemporary phrase – was the basis of Chinese cartography for centuries.

Chang Heng’s grid made no allowance for the curvature of the Earth, and it is hard to know from what is left of ancient Eastern cartography whether his image of a spherical world had any effect on current thought. There are no indications that early Chinese mapmakers realized the world was a sphere, that the lands they were mapping were consequently curved, nor whether the challenge, which still fascinates cartographers, of representing such a three-dimensional world on a flat surface had even occurred to them as a problem.

In the Islamic world, Arab mapmakers drew on the ideas of Ptolemy and the Greeks to develop their own traditions. By the eighth century, they were compiling maps for overland diplomatic missions to China, military campaigns, and trading expeditions; the tales of Sindbad the Sailor, dating from some two hundred years earlier, are ample evidence of their seafaring traditions. Unlike the work produced by medieval monks in Europe, their maps seem to have been designed for use as much as for study, but they were still based mainly on copies of older European originals. There are early versions of the T-O maps, with south at the top and Mount Sinai in the center and, slightly later, more distinctively Arab interpretations in which a disk-shaped world, surrounded by water, is pierced from the east by the Arabian Gulf and the Red Sea, and from the west by the waters of the Mediterranean.

Later mapmakers of the tenth and eleventh centuries were often slave dealers or traders, making their way north to the shores of the Caspian Sea and up the Volga River deep into the heart of Asia. Asian tribesmen, Russians, Norsemen, and Arabs would meet on one of the medieval world’s great trading routes, exchanging goods, knowledge, and ideas.

One account, by the writer Ibn Haukal, author of The Book of Roads and Kingdoms, which contained a map of the Islamic world as it was then known, described a meeting toward the end of the tenth century with the great Arab cartographer al-Istakhri. “He showed me the geographical maps in his work, and, when I had commented on them, he gave me his work with the words, ‘I can see that you were born under a lucky star, therefore take my work and make such improvements as you think fit.’ I took it, altered it in several particulars, and returned it to him.”

There was cooperation not just between individuals but between cultures. One of the greatest of all the Arab cartographers, Muhammed al-Idrisi, was born in Morocco, studied at Cordoba in Islamic Spain, and worked at the twelfth-century court of the Christian king Roger of Sicily. There, he produced several world maps that drew directly both on Ptolemy and on the observations of Arab travelers, and which were still being used as models by Islamic cartographers four hundred years later. Among them were a large rectangular map in seventy sheets, and a smaller, circular map, similar to the T-O maps of the West, but incorporating curved parallels, which suggest that al-Idrisi was aware of the spherical shape of the world. The maps and sources that he used are lost, but the geographic detail he provided was far in advance of anything that was being produced by the copyists in Europe’s monasteries. Al-Idrisi’s representation of Spain, for example, with the northern coast of Africa, the Straits of Gibraltar, and Bay of Biscay all clearly discernible, is far more detailed than the stylized version presented around the same time by European mapmakers. When Al-Idrisi described Britain as “a great island, shaped like the head of an ostrich,” and the peninsula of Cornwall as “like a bird’s beak,”

he had evidently been studying more accurate maps than anything available in Europe.

DESPITE ITS ULTIMATE INFLUENCE in Europe, for hundreds of years after publication of the Geographia, Christian scholars turned their backs on Ptolemy’s knowledge. With the fall of the Roman Empire, the original manuscripts that Ptolemy had written in the second century were lost and forgotten. For the medieval scribes of the early Church, the old T-O maps compiled in the centuries before Ptolemy had the great advantage that they could easily be adapted to place the holy city of Jerusalem at the center of the world, as the Bible itself decreed.

For them, as for the Greek philosophers, the sea was a fitting symbol to represent the mysteries that bounded man’s little area of knowledge on every side. What had not been established by exploration was supplied by imagination or faith; the maps that the medieval Christian scholars drew were therefore inaccurate, impressionistic expressions of belief, not descriptions of fact.

Some of these great mappaemundi, the medieval pictures of the world, were also works of art of staggering beauty. Most of them are lost, but in the English cathedral city of Hereford, it is still possible to glimpse the vision of the world that was in men’s minds on the eve of the age of discoveries. The great Hereford mappamundi dates from the last years of the thirteenth century.

Even after a visitor to the cathedral has puzzled out the fact that, as on almost all early maps, east is to the top, and has spotted the outline of the Mediterranean Sea that divides the world down the middle, the coastlines and landforms are almost unrecognizable. There is no mistaking the traditional T-shape of great waters surrounded by the O of the ocean, although the lands are threaded with rivers. The British Isles clutch grimly to the perimeter of Europe, twisted and misshapen; instead of the familiar boot shape of Italy, there is a bloated peninsula, dotted with apparenty random cities and ribbed with unknown rivers. The names of Europe and Africa are transposed, probably a mistake by the copyist. Indeed, the map as a whole seems to be sketched more in hope than in conviction. Any modern classroom could produce a dozen more realistic views of the world. Ptolemy would have scoffed.

Yet the Hereford mappamundi has its own confidence, as befits the only complete wall map of the world known to have survived from the Middle Ages. It speaks the language of another age. What were once its bright colors are faded and browned into a dull ochre that challenges the eyes, while the drawings that crowd the map seem almost to jostle each other aside; it takes a while to focus on them individually, to see the delicacy and precision with which they are sketched in. Carefully drawn towers and turrets mark some of the cities of which the map-maker had heard: The familiar names of the Bible are clustered around Jerusalem, and, closer to home, Paris, Ghent, and even Hereford itself are marked. But it is a work to be interpreted, rather than simply consulted; a statement of belief.

Medieval library catalogs show that there were few monasteries or noble palaces without such maps in their stores of manuscripts. Charlemagne, at the end of the eighth century, had plans of Rome and Constantinople engraved on silver tablets among a comprehensive collection, and most great libraries would have included maps of the Holy Land as well as the great mappaemundi – triumphs and baubles for the rich and mighty, and reminders for the humble poor of their place in the great scheme of being. Few survived. A sister-map of the Hereford mappamundi, the Ebsdorf map, was rediscovered in a Benedictine monastery in the German town whose name it bears after being lost for six hundred years, only to be destroyed by Allied bombing during World War II. Now it survives only in modern copies and photographs. The history of cartography is the tantalizing study of what has been left behind.

The Hereford mappamundi

Hereford Cathedral Library, Hereford, England

The worldview of the mappaemundi encompassed the soul as well as time and space. The Hereford map, for example, shows not only the towns of the Holy Land but also the expulsion of Adam and Eve from Eden and Noah riding on the waters of the Flood. It admits no conflict between geographic accuracy and religious faith: The holy city of Jerusalem stands unchallenged at the center of the world, while Paradise itself is shown far away in the apparently unreachable East, a round island circled by flames that warn the importunate traveler not to dare too much.

The mappaemundi may have been used for planning journeys from town to town across Europe – marks over the great central city of Paris on the Hereford map suggest that fingernails may have traced a route through it at various times – but it mattered little to the mapmaker that the shape of the coastlines should be so inaccurate, or that the whole map should have been shoehorned so ruthlessly into an all-embracing circle of ocean. Much more important, from his standpoint, God had to be shown overseeing the whole of his kingdom, and the fabulous creatures described by the ancients, such as the bonnacan, with its bull’s head, horse’s mane, and ram’s horns, the screaming mandrake plant, and the death-dealing cockatrice, needed to be faithfully represented to demonstrate the awesome variety of his Creation.

The Hereford mappamundi laid out a world at once mysterious and threatening, where the only hope of safety was to be found in the majestic figure of Christ that dominates the map. To criticize it for inaccuracy would be as foolish as to find fault with Picasso’s famous painting as a street guide to Guernica. Yet for the rapidly growing world of the fifteenth and sixteenth centuries, the mappaemundi were quickly proved inadequate. A new geography was needed to enable sailors to plot a reliable course across the oceans and to represent the world they were revealing.