Gerardus Mercator

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A separate article is about the mathematician Nicholas Mercator.

Gerardus Mercator (March 5, 1512 – December 2, 1594) was a Flemish cartographer. He was born in Rupelmonde in East Flanders in the Holy Roman Empire of the German Nation to parents from Gangelt in the Duchy of Jülich (modern Germany). He lived since 1552 in Duisburg. He is remembered for the Mercator chart named after him.

Mercator was born Gheert Cremer (or Gerard de Cremere) in the Flemish town of Rupelmonde. "Mercator" is the Latinized form of his name. It means "merchant" or "marketeer". He was educated in 's-Hertogenbosch by the famous humanist Macropedius and at the University of Leuven. Despite his fame as a cartographer, Mercator's main source of income came through his craftmanship of mathematical instruments. He returned to Leuven and worked with Gemma Frisius and Gaspar Myrica. They worked together from 1535 to 1536 to construct a terrestrial globe, although the role of Mercator in the project was not primarily as a cartographer, but as a highly skilled engraver of brass plates. Mercator's own independent map-making only began when he produced a map of Palestine in 1537, and this was followed by another map of the world (1538) and a map of Flanders (1540). During this period he learned Italic script since it was the most suitable type of script for copper engraving of maps. He wrote the first instruction book of Italic script published in northern Europe.

Mercator map of Europe

Mercator was convicted of heresy in 1544 because of his wide travels and Protestant faith; he spent seven months in prison. ^[1]

In 1552, he moved to Duisburg, one of the major cities in the German Duchy of Cleves. He opened a cartographic workshop, where he completed a six-panel map of Europe in 1554. He also worked as a surveyor for the city. His motives for moving to Duisburg are not clear. Mercator might have left the Netherlands for religious reasons or because he was informed about the plans to found a university. He taught mathematics at the academic college of Duisburg. After producing several maps he was appointed Court Cosmographer to the Duke Wilhelm of Cleve in 1564. He constructed a new chart and first used it in 1569; it had parallel lines of longitude to aid navigation by sea, as compass courses could be marked as straight lines.

Rumold's world map, drawn in 1587 after his father's map of 1567 (published in 1595)

He took the word atlas to describe a collection of maps, and encouraged Abraham Ortelius to compile the first modern world atlas, Theatrum Orbis Terrarum in 1570. He produced his own atlas in a number of parts, the first of which was published in 1578 and consisted of corrected versions of the maps of Ptolemy (though introducing a number of new errors). Maps of France, Germany and the Netherlands were added in 1585 and of the Balkans and Greece in 1588, further maps were published in 1595 after his death by his son Rumold Mercator.

Mercator devised a technique to produce globes— celestial as well as terrestrial— by techniques of relative mass production. Globes at the time were laboriously produced by engraving upon a sphere of wood or gilded brass. Mercator moulded globes of papier-mâché on a wooden mould, then cut them along the equator; once reassembled, the globes were applied with gesso, a white mixture of thin plaster and sizing. Mercator engraved and printed sets of world maps on twelve tapering gores, with curved edges that narrowed towards the poles, which were cut out and applied to the globe. Circular engraved caps covered the ends at the poles. After the globes were hand-tinted with watercolors they were set in wooden stands with calibrated brass horizon rings. Twenty-two such pairs of Mercator globes have survived.

After moving to Duisburg Mercator never left the city and died there a respected and wealthy citzen. He was buried in the city's main cathedral of Saint Salvatorus. Exhibits of his works can be seen in the Mercator treasury located in the city.

More exhibits about Mercator's life and work are featured at the Mercator Museum in Sint-Niklaas, Belgium.