It is no great matter whether those that die on this account be guilty or innocent, provided we terrify the people by these examples; which generally succeeds best, when persons eminent for learning, riches, nobility or high stations, are thus sacrificed.
Six years later, in 1518, the Kremers moved back to Rupelmonde, possibly motivated by the deteriorating conditions in Gangelt—famine, plague and lawlessness. Mercator would have attended the local school in Rupelmonde from the age of seven, when he arrived from Gangelt, and there he would have been taught the basics of reading, writing, arithmetic and Latin.
In between these works he found time to write Literarum latinarum, a small instruction manual on the italic script. The italic script (or chancery cursive) reached the Low Countries from Italy at the beginning of the sixteenth century and it is recorded as a form of typescript in Leuven in 1522. It was much favoured by humanist scholars who enjoyed its elegance and clarity as well as the rapid fluency that could be attained with practice, but it was not employed for formal purposes such as globes, maps and scientific instruments (which typically used Roman capitals or gothic script). Mercator first applied the italic script to the globe of Gemma Frisius and thereafter to all his works, with ever-increasing elegance. The title page of this work is an illustration of the decorative style he developed.
After Hubert's death in 1526, Gisbert became Mercator's guardian. Hoping that Mercator might follow him into the priesthood, he sent the 15-year-old Geert to the famous school of the Brethren of the Common Life at 's-Hertogenbosch in the Duchy of Brabant. The Brotherhood and the school had been founded by the charismatic Geert Groote who placed great emphasis on study of the bible and, at the same time, expressed disapproval of the dogmas of the church, both facets of the new "heresies" of Martin Luther propounded only a few years earlier in 1517. Mercator would follow similar precepts later in life – with problematic outcomes.
Gemma and Gaspar Van der Heyden had completed a terrestrial globe in 1529 but by 1535 they were planning a new globe embodying the latest geographical discoveries. The gores were to be engraved on copper, instead of wood, and the text was to be in an elegant italic script instead of the heavy Roman lettering of the early globes. The globe was a combined effort: Gemma researched the content, Van der Heyden engraved the geography and Mercator engraved the text, including the cartouche which exhibited his own name in public for the first time. The globe was finished in 1536 and its celestial counterpart appeared one year later. These widely admired globes were costly and their wide sales provided Mercator an income which, together with that from mathematical instruments and from teaching, allowed him to marry and establish a home. His marriage to Barbara Schellekens was in September 1536 and Arnold, the first of their six children, was born a year later.
From a famous school, Mercator moved to the famous University of Leuven, where his full Latin name appears in the matriculation records for 1530. He lived in one of the teaching colleges, the Castle College, and, although he was Classified as a pauper, he rubbed shoulders with richer students amongst whom were the Anatomist Andreas Vesalius, the statesman Antoine Perrenot, and the theologian George Cassander, all destined to fame and all lifelong friends of Mercator.
The general first degree (for Magister) centred on the teaching of philosophy, theology and Greek under the conservative Scholasticism which gave prime place to the authority of Aristotle. Although the trivium was now augmented by the quadrivium (Arithmetic, Geometry, Astronomy, Music), their coverage was neglected in comparison with theology and philosophy and consequently Mercator would have to resort to further study of the first three subjects in years to come. Mercator graduated Magister in 1532.
Towards the end of 1534, the 22 year old Mercator arrived back in Leuven and threw himself into the study of geography, mathematics and astronomy under the guidance of Gemma Frisius. Mercator was completely out of his depth but, with the help and friendship of Gemma, who was only four years older, he succeeded in mastering the elements of mathematics within two years and the university granted him permission to tutor private students. Gemma had designed some of the mathematical instruments used in these studies and Mercator soon become adept in the skills of their manufacture: practical skills of working in brass, mathematical skills for calculation of scales and engraving skills to produce the finished work.
Working alongside Gemma whilst they were producing the globes, Mercator would have witnessed the process of progressing geography: obtaining previous maps, comparing and collating their content, studying geographical texts and seeking new information from correspondents, merchants, pilgrims, travellers and seamen. He put his newly learned talents to work in a burst of productivity. In 1537, aged only 25, he established his reputation with a map of the Holy Land which was researched, engraved, printed and partly published by himself.
A year later, in 1538, he produced his first map of the world, usually referred to as Orbis Imago. In 1539/40 he made a map of Flanders and in 1541 a terrestrial globe. All four works were received with acclaim and they sold in large numbers. The dedications of three of these works witness Mercator's access to influential patrons: the Holy Land was dedicated to Franciscus van Cranevelt who sat on the Great Council of Mechelen, the map of Flanders was dedicated to the Emperor himself and the globe was dedicated to Nicholas Perronet, the emperor's chief advisor. The dedicatee of the world map was more surprising: Johannes Drosius, a fellow student who, as an unorthodox priest, may well have been suspected of Lutheran heresy. Given that the symbolism of the Orbis Imago map also reflected a Lutheran view point, Mercator was exposing himself to criticism by the hardline Theologians of Leuven .
In 1542, the thirty year old must have been feeling confident about his Future prospects when he suffered two major interruptions to his life. First, Leuven was besieged by the troops of the Duke of Cleves, a Lutheran sympathiser who, with French support, was set on exploiting unrest in the Low Countries to his own ends. Ironically it was this same Duke to whom Mercator would turn ten years hence. The siege was lifted but the financial losses to the town and its traders, including Mercator, were great. The second interruption was potentially deadly: the Inquisition called.
It may well have been these Inquisitors who, in 1543, decided that Mercator was eminent enough to be sacrificed. His name appeared on a list of 52 Lutheran heretics which included an Architect, a Sculptor, a former rector of the university, a monk, three Priests and many others. All were arrested except Mercator who had left Leuven for Rupelmonde on Business concerning the estate of his recently deceased uncle Gisbert. That made matters worse for he was now Classified as a fugitive who, by fleeing arrest, had proved his own guilt.
Mercator never committed any of his prison experiences to paper; all he would say was that he had suffered an "unjust persecution". For the rest of his time in Leuven his religious thoughts were kept to himself and he turned back to his work. His brush with the Inquisition did not affect his relationship with the court and Nicholas Perrenot recommended him to the Emperor as a maker of superb instruments. The outcome was an Imperial order for globes, compasses, astrolabe and astronomical rings. They were ready in 1545 and the Emperor granted the royal seal of approval to his workshop. Sadly they were soon destroyed in the course of the Emperor's military ventures and Mercator had to construct a second set, now lost. He also returned to his work on a large up-to-date and highly detailed wall map of Europe which was, he had already claimed on his 1538 world map, very well advanced. It proved to be a vast task and he, perfectionist that he was, seemed unable to cut short his ever-expanding researches and publish: as a result it was to be another ten years before the map appeared.
In 1547 Mercator was visited by the young (nineteen year old) John Dee who, on completion of his undergraduate studies in Cambridge (1547), "went beyond the seas to speak and confer with some learned men". Dee and Mercator were both passionately interested in the same topics and they quickly established a close rapport which lasted throughout their lives. In 1548 Dee returned to Leuven (Louvain in Dee's text) and registered as a student: for three years he was constantly in Mercator's company. Apart from a possible short visit to Duisberg in 1562 the two men did not meet but they corresponded frequently and by good fortune a number of their letters are preserved. Dee took maps, globes and astronomical instruments back to England and in return furnished Mercator with the latest English texts and new geographical knowledge arising from the English explorations of the world. Forty years later they were still cooperating, Dee using Mercator's maps to convince the English court to Finance Martin Frobisher's expeditions and Mercator still avidly seeking information of new territories.
The final success in Leuven was the 1551 celestial globe, the partner of his terrestrial globe of 1541. The records of the Plantin Press show that several hundred pairs of globes were sold before the end of the century despite their high price—in 1570 they sold at 25 carolus guilders for a pair, equivalent to 2500 euro in modern currency. Celestial globes were a necessary adjunct to the intellectual life of rich patrons and academics alike, for both astronomical and astrological studies, two subjects which were strongly entwined in the sixteenth century. Twenty two pairs are still in existence.
In 1552 Mercator moved from Leuven to Duisburg in the Duchy of Cleves. He never gave his reasons for the move but several factors may have been involved: not having been born in Brabant he could never be a full citizen of Leuven; Catholic intolerance of religious dissidents in the Low Countries was becoming ever more aggressive and a man suspected of heresy once would never be trusted; the Erasmian constitution and the religious tolerance of Cleves must have appeared attractive; there was to be a new university in Duisburg and teachers would be required. He was not alone; over the years to come many more would flee from the oppressive Catholicism of Brabant and Flanders to tolerant cities such as Duisburg.
In 1554 Mercator published the long-awaited wall map of Europe, dedicating it to his friend, now Cardinal, Antoine Perrenot. He had worked at it for more than twelve years, collecting, comparing, collating and rationalising a vast amount of data and the result was a map of unprecedented detail and accuracy. It "attracted more praise from scholars everywhere than any similar geographical work which has ever been brought out." It also sold in large quantities for much of the rest of the century with a second edition in 1572 and a third edition in the atlas of 1595.
The proposed university in Duisburg failed to materialize because the papal licence to found the University was delayed twelve years and by then Duke Wilhelm had lost interest. It was another 90 years before Duisburg had its university. On the other hand, no papal permit was required to establish the Akademisches Gymnasium where, in 1559 Mercator was invited to teach mathematics with cosmography. One year later, in 1560, he secured the appointment of his friend Jan Vermeulen (Molanus) as rector and then blessed Vermeulen's marriage to his daughter Emerantia. His sons were now growing to manhood and he encouraged them to embark on his own profession. Arnold, the eldest, had produced his first map (of Iceland) in 1558 and would later take over the day-to-day running of Mercator's enterprises. Bartholemew, his second son, showed great academic promise and in 1562 (aged 22) he took over the teaching of his father's three year long lecture-course—after Mercator had taught it once only! Much to Mercator's grief, Bartholemew died young, in 1568 (aged 28). Rumold, the third son, would spend a large part of his life in London's publishing houses providing for Mercator a vital link to the new discoveries of the Elizabethan age. In 1587 Rumold returned to Duisburg and later, in 1594, it fell to his lot to publish Mercator's works posthumously.
The trip to Lorraine in 1564 was a set back for his health but he soon recovered and embarked on his greatest project yet, a project which would extend far beyond his cartographic interests. The first element was the Chronologia, a list of all significant events since the beginning of the world compiled from his literal reading of the bible and no less than 123 other authors of genealogies and histories of every empire that had ever existed. Mercator was the first to link historical dates of solar and lunar eclipses to Julian dates calculated mathematically from his knowledge of the motions of the sun, moon and Earth. He then fixed the dates of other events in Babylonian, Greek, Hebrew and Roman calendars relative to the eclipses that they recorded. The time origin was fixed from the genealogies of the Bible as 3965 years before the birth of Christ. This huge volume (400 pages) was greeted with acclaim by scholars throughout Europe and Mercator himself considered it to be his greatest achievement up to that time. On the other hand, the Catholic Church placed the work on the Index Librorum Prohibitorum (List of Prohibited Books) because Mercator included the deeds of Martin Luther. Had he published such a work in Louvain he would again be laying himself open to charges of heresy.
As the Chronologia was going to press in 1569, Mercator also published what was to become his most famous map: Nova et Aucta Orbis Terrae Descriptio ad Usum Navigantium Emendate Accommodata (A new and more complete representation of the terrestrial globe properly adapted for use in navigation). As mariners had started to explore the oceans in the Age of Discovery the Problem of accurate navigation had become more pressing. Their locations could be a hundred miles out after a long voyage because a course of constant direction at sea (a rhumb line) did not correspond to a straight line on their chart. Mercator's solution was to make the scale of his chart increase with latitude in a very special way such that the rhumb lines became straight lines on his new world map. Exactly how he arrived at the required solution is not recorded in any of his own written works but modern scholars suggest that he used the tables of rhumbs devised by Pedro Nunes. The large size of what was a wall map meant that it did not find favour for use on board ship but, within a hundred years of its creation, the Mercator Projection became the standard for marine charts throughout the world and continues to be so used to the present day. On the other hand the projection is clearly unsuitable as a description of the land masses on account of its manifest distortion at high latitudes and its use is now deprecated: other projections are more suitable. Although several hundred copies of the map were produced it soon became out of date as new discoveries showed the extent of Mercator's inaccuracies (of poorly known lands) and speculations (for Example, on the arctic and the southern continent).
Mercator was one of the founders of the Netherlandish school of cartography and is widely considered as the most notable representative of the school in its golden age (approximately 1570s–1670s). In his own day he was the world's most famous geographer but, in addition, he had interests in theology, philosophy, history, mathematics and geomagnetism as well as being an accomplished engraver, calligrapher and maker of globes and scientific instruments.
Apart from a revision of the map of Europe in 1572 there would be no more large wall maps and Mercator began to address the other tasks that he had outlined in the Cosmographia. The first of these was a new definitive version of Ptolemy's maps. That he should wish to do so may seem strange given that, at the same time, he was planning very different modern maps and other mapmakers, such as his friend Abraham Ortelius, had forsaken Ptolemy completely. It was essentially an act of reverence by one scholar for another, a final epitaph for the Ptolemy who had inspired Mercator's love of geography early in his life. He compared the great many editions of the Ptolemy's written Geographia, which described his two projections and listed the latitude and longitude of some 8000 places, as well as the many different versions of the printed maps which had appeared over the previous one hundred years, all with errors and accretions. Once again, this self-imposed diligence delayed publication and the 28 maps of Ptolemy appeared in 1578, after an interval almost ten years. It was accepted by scholars as the "last word", literally and metaphorically, in a chapter of geography which was closed for good.
Mercator now turned to the modern maps, as author but no longer engraver: the practicalities of production of maps and globes had been passed to his sons and grandsons. In 1585 he issued a collection of 51 maps covering France, the Low Countries and Germany. Other maps may have followed in good order had not the misfortunes of life intervened: his wife Barbara died in 1586 and his eldest son Arnold died the following year so that only Rumold and the sons of Arnold were left to carry forward his Business. In addition, the time he had available for cartography was reduced by a burst of writing on philosophy and theology: a substantial written work on the Harmonisation of the Gospels as well as commentaries on the epistle of St. Paul and the book of Ezekiel. In 1589, at the age of 77, Mercator had a new lease of life. He took a new wife, Gertrude Vierlings, the wealthy widow of a former mayor of Duisburg (and at the same time he arranged the marriage of Rumold to her daughter). A second collection of 22 maps was published covering Italy, Greece and the Balkans. This volume has a noteworthy preface for it includes the first mention of Atlas as a mythical king of Mauretania, a son of the globe-bearing Titan of the same name. "I have set this man Atlas," explained Mercator, "so notable for his erudition, humaneness, and wisdom as a model for my imitation." A year later, Mercator had a stroke which left him greatly incapacitated. He struggled with the assistance of his family trying to complete the remaining maps, the ongoing theological publications and a new treatise on the Creation of the World. This last work, which he did succeed in finishing, was the climax of his life's activities, the work which, in his own opinion, surpassed all his other endeavours and provided a framework and rationale for the complete atlas. It was also his last work in a literal sense for he died after two further strokes in 1594.
The atlas was not an immediate success. One reason may have been that it was incomplete: Spain was omitted and there were no detailed maps outside Europe. Rumold avowed that a second volume would attend to these deficiencies but it was not forthcoming and the whole project lost momentum; Rumold, who was 55 years old in 1595, was in decline and died in 1599. His family did produce another edition in 1602 but only the text was reset, there were no new maps. Another reason for the failure of the Atlas was the strength of the continuing sales of the Theatrum Orbis Terrarum of Abraham Ortelius. Alongside the sumptuous maps of that book Mercator's un-ornamented new maps looked very unattractive. Despite the death of Ortelius in 1598 the Theatrum flourished: in 1602 it was in its thirteenth Latin edition as well as editions in Dutch, Italian, French, German and Spanish. The Mercator atlas seemed destined for oblivion.
Mercator's editions of Ptolemy and his theological writings were in print for many years after the demise of the atlas but they too eventually disappeared and it was the Mercator projection which emerged as his sole and greatest legacy. His construction of a chart on which the courses of constant bearing favoured by mariners appeared as straight lines ultimately revolutionised the art of navigation, making it simpler and therefore safer. Mercator left no hints to his method of construction and it was Edward Wright who first clarified the method in his book Certaine Errors (1599)—the relevant error being the erroneous belief that straight lines on conventional charts corresponded to constant courses. Wright's solution was a numerical approximation and it was another 70 years before the projection formula was derived analytically. Wright published a new world map based on the Mercator projection, also in 1599. Slowly, but steadily, charts using the projection appeared throughout the first half of the seventeenth century and by the end of that century chart makers all over the world were using nothing but the Mercator projection, with the aim of showing the oceans and the coastlines in detail without concern for the continental interiors. At some stage the projection made the unfortunate leap to portrayal of the continents and it eventually became the canonical description of the world, despite its manifest distortions at high latitudes. Recently Mercator's projection has been rejected for representations of the world but it remains paramount for nautical charts and its use stands as his enduring legacy.
The sale catalogue doesn't mention any maps but it is known that the family sold the copper plates to Jodocus Hondius in 1604. He transformed the atlas. Almost 40 extra maps were added (including Spain and Portugal) and in 1606 a new edition appeared under his name but with full acknowledgement that most maps were created by Mercator. The title page now included a picture of Hondius and Mercator together although they had never met. Hondius was an accomplished Business man and under his guidance the Atlas was an enormous success; he (followed by his son Henricus, and son-in-law Johannes Janssonius) produced 29 editions between 1609 and 1641, including one in English. In addition they published the atlas in a compact form, the Atlas Minor, which meant that it was readily available to a wide market. As the editions progressed, Mercator's theological comments and his map commentaries disappeared from the atlas and images of King Atlas were replaced by the Titan Atlas. By the final edition the number of his maps in the atlas declined to less than 50 as updated new maps were added. Eventually the atlas became out-of-date and by the middle of the seventeenth century the publications of map-makers such as Joan Blaeu and Frederik de Wit took over.
Mercator's nationality is contentious. In 1868, in preparation for the 300th anniversary of the famous world map of 1569, the Belgian Jean Van Raemdonck published a biography of Mercator as the Flemish geographer, in which he presented a speculative Cremer family tree with ancestors in Rupelmonde. In 1869, in Duisburg, Arthur Breusing published a small book on Mercator as the German geographer, in which he claimed that the family was from Jülich, Mercator was conceived there, and consequently his birth during the visit to Rupelmonde didn't invalidate his German nationality. The debate continued in 1914 when Heinrich Averdunk attacked Van Raemdonck's 'fictions' and argued that the many occurrences of the name Kremer in Jülich in the sixteenth century supported Breusing's claim that the family was German. Today, many Belgians and Germans still claim Mercator as their own, despite the lack of any evidence pertaining to the birthplace and background of his father, Hubert. Most modern scholars adopt a neutral position, hesitating to assign a nationality to Mercator, but many popular accounts simply plump for one nation or another without evidence.
During his time at the school the headmaster was Georgius Macropedius, and under his guidance Geert would study the Bible, the trivium (Latin, logic and rhetoric) and classics such as the philosophy of Aristotle, the natural history of Pliny and the geography of Ptolemy. All teaching at the school was in Latin and he would read, write and converse in Latin – and give himself a new Latin name, Gerardus Mercator Rupelmundanus, Mercator being the Latin translation of Kremer, which means "merchant". The Brethren were renowned for their scriptorium and here Mercator might have encountered the italic script which he employed in his later work. The brethren were also renowned for their thoroughness and discipline, well attested by Erasmus who had attended the school forty years before Mercator.
Following Mercator's death his family prepared the Atlas for publication—in four months. It was, after all, a hoped for source of the income that was needed to support them. This work entailed supplementing the maps of the 1585 and 1589 with 28 unpublished maps of Mercator covering the northern countries, creating four maps of the continents and a world map, the printing of Mercator's account of the creation and finally the addition of eulogies and Walter Ghim's biography of Mercator. The title itself provides Mercator's definition of a new meaning for the word "Atlas": Atlas Sive Cosmographicae Meditationes de Fabrica Mundi et Fabricati Figura which may be translated as "Atlas or cosmographical meditations upon the fabric of the world and the figure of the fabrick’d, or, more colloquially, as Atlas or cosmographical meditations upon the creation of the universe, and the universe as created." Over the years Mercator's definition of atlas has become simply A collection of maps in a volume.