When Emerentia Kremer, wife of a humble shoemaker, gave birth to her seventh child on 5 March 1512 in St Johann hospice in Rupelmonde, little did she know the worldwide fame that baby Gerard would go on to enjoy.

Emerentia and her husband, Hubert, were actually in Rupelmonde, now part of the town of Kruibeke in East Flanders, by chance, having travelled from their home town of Gangelt in Germany to visit Hubert’s brother, Gisbert. A few weeks after Gerard’s birth, they returned to Gangelt but felt drawn back to Flanders in 1518 to make Rupelmonde their home.

Six-year-old Gerard began attending the local school, where he studied Latin, religion and arithmetic. Within one year, he was able to speak and read Latin fluently.

When Gerard was 15, his father died, leaving Uncle Gisbert, a priest, as his guardian. Gisbert wanted the best education possible for Gerard, so in 1527 he sent him to be educated with the Brethren of the Common Life in ’s Hertogenbosch (now in the Netherlands, then part of the Duchy of Brabant).

While Gerard was there, his mother died, and he chose a new name for himself. Kremer means “merchant” in German, so he chose Mercator, the Latin term for “merchant”, and gave himself the full name of Gerardus Mercator Rupelmundanus.

Piecing the world together

In 1530, Mercator enrolled at the University of Leuven (then already a 100-year-old institution), taking courses in humanities and philosophy before studying mathematics under Gemma Frisius. He also learnt about the application of mathematics to geography and astronomy, which he found “extremely agreeable”, writing: “I liked, little by little, not only the description of the earth, but also the structure of the whole machinery of the world, whose numerous elements are not known by anyone to date.”

During this time, Mercator learned to be an engraver and to construct instruments, and he began to make mathematical instruments of exceptional quality. One of these, made in 1535, was a terrestrial globe commissioned by the Emperor Charles V.

Mercator married Barbara Schelleken in 1536, and they had six children – three daughters and three sons. In 1537, he constructed a globe of the stars as well as his first map – of Palestine. The following year, he produced his first map of the world; it was notable for being the first to represent America as stretching from the northern regions to the southern regions and for giving North America its name. His map of Flanders followed in 1540.

Never trust a sailor

In the summer of 1540, Mercator started on his most ambitious project yet: maps of the regions of the world that would then be combined to form a giant world map. One of the problems he faced was incorrect data from sailors, who assumed that if they followed a particular compass course, they would travel in a straight line.

Mercator realised that a ship sailing towards the same point of the compass would follow a curve called a loxodrome (also called a rhumb line). The globe that Mercator produced in 1541 was the first to show rhumb lines.

In February of 1544, Mercator was arrested and charged with heresy, on the basis of his sympathy for Protestant beliefs and suspicions about his frequent travels. His house was searched but nothing was found to suggest he was not a good Roman Catholic. However, he still spent seven months in prison in Rupelmonde Castle, eventually being released with the help of scholars at the University of Leuven.

A man in demand

Having had to pay for the cost of his own imprisonment, Mercator found himself in a poor financial position. He therefore put in overtime building mathematical instruments and worked on a celestial globe of the same size as his terrestrial globe of 1541, which he completed in 1551. The following year, Mercator and his family moved to Duisburg, Germany, where he opened a cartographic workshop. A new university was planned for the town, so there was a large demand for mathematical instruments, books, maps and globes. He still had time to produce a huge new map of Europe measuring 1.6 by 1.3 metres, which re-established him as the leading European mapmaker. His income secure, he and his family moved into a large house in the wealthiest district of Duisburg.

The Mercator projection

Further maps followed, including one of the British Isles in 1564. That year he was appointed Court Cosmographer to Duke Wilhelm of Cleve. During this period, he began to perfect a new map projection, the one for which he is best remembered.

He first used the Mercator projection in 1569 for a wall map of the world on 18 separate sheets, which he called “A new and more complete representation of the terrestrial globe properly adapted for its use in navigation”. With the Mercator projection, lines of longitude and latitude and rhomb lines all appeared as straight lines on the map. He was also the first to use the term “atlas”, naming his map collection after the mythological figure who was said to hold up the world on his broad shoulders.

In his old age, Mercator published corrected and updated versions of Ptolemy’s maps, followed by a series of maps of France, Germany, the Netherlands, the Balkans and Greece. In May of 1590, Mercator had a stroke, which left his left side paralysed. He slowly recovered but was greatly frustrated at his inability to continue mapmaking, and by 1592 he was virtually blind.

Two more strokes led to Mercator’s death on 2 December 1594 at the ripe age of 82. Some maps that were incomplete at his death were finished and published by his son in 1595.

The English mathematician Edward Wright (1561-1615) explained the details of the Mercator projection in his book Certaine Errors in Navigation, published in 1599, and is therefore credited with presenting the Mercator projection to the world.

Mercator goes digital

To commemorate the 500th anniversary of Mercator’s birth, SteM, the city museum of Sint- Niklaas, hosts an eye-catching exhibition, a series of lectures and an international cartographic conference.

The centrepiece is Mercator Digitaal, which includes Mercator’s original globe from 1541, his celestial globe from 1551 and a series of his atlases. Seven kiosks, meanwhile, house “digital presentations of various aspects of Mercator’s life and work, placing them into a contemporary context,” explains project manager Harry Van Royen. “The 51 constellations of his celestial globe are illuminated one by one, and the secrets of the world-famous Mercator projection are explained.”

In video clips, Flemish actor Vic De Wachter assumes the role of Mercator and takes you to the places where he lived and worked. Fifteen contemporaries of Mercator, including his first wife, fellow cartographers and key patrons, are also “interviewed” to bring his works to life. Interactive touch-screens give you a unique opportunity to digitally page through three Mercator atlases dating back to 1584, 1595 and 1607, and there is also access to the digital map of Flanders (1540). Here you can zoom in on historical maps and recent topographic aerial photographs.

That’s not all. “There is also an exhibit of Mercator’s own library, special walks, a kinetic art project called Homo Universalis and an international cartographic conference organised with the SteM and the University of Ghent,” says Van Royen, adding that events for younger children include workshops in which they can draw their own maps, while older children can create a map using triangulation.

There is also a series of lectures describing details of the original Mercator items on display and subjects related to cartography. Most of the lectures are in Dutch, but the one by Professor Gerry Brotton from Queen Mary University of London on 24 April is in English. Called “Mapping the World: From the Greeks to Google Earth”, it will cover the evolution of our world from a map in a book to the digital processing of space images.

And if you’re still thirsty for more, don’t forget the four-day international conference “Mercator Revisited: Cartography in the Age of Discovery”, which begins on 25 April.

Protecting the heritage

That such a vast collection of original Mercator material can be displayed in one room is thanks to the excellent work of the Oudheidkundige Kring van het Land van Waas (Antiquities Society for the County of Waas).

“Founded in 1861, one of the society’s aims was to commemorate Mercator by finding and buying his original globes and atlases,” explains Ward Bohé, the curator of Sint-Niklaas’ city museum SteM. “They worked tirelessly to track these down and bring them to Sint-Niklaas, where they could be properly looked after. It’s largely due to their efforts that we are able to stage the exhibition Mercator Digitaal.”

www.mercatordigitaal.be