Gerardus Mercator modernized cartography with the "Mercator projection," or the depiction of the world using straight lines for latitude and longitude. Although this representation necessarily distorted actual geography as it moved away from the equator toward the poles, it enabled sailors to navigate accurately with the aid of maps. This development acted as a boon to nautical navigation, an important step in the age of geographic discovery. Although it has proven impossible to completely reconcile Mer-cator’s two-dimensional projection with three-dimensional reality, the Mercator projection remains in use by navigators more than four centuries after its invention.
Mercator was born Gerhard Kremer (or Gerard du Cremer) on March 5, 1512, in Rupel-monde, Flanders (now Roermonde, Holland). His father was a poor shoemaker, but he was raised by his uncle, Gisbert Mercator, a wealthy ecclesiastic who sent Mercator to the ‘s-Hertogenbosch school at the House of the Brethren of the Common Life. There, he received an education in philosophy and theology that customarily prepared students for the priesthood. In 1530, he entered the University of Louvain in Belgium, at which point he latinized his name to Gerardus Mercator. Two years later, he received a master of arts degree.
After graduation, Mercator traveled to Mechelen and Antwerp before returning to Lou-vain, where he apprenticed in engraving under Gemma Frisius, who also taught him mathematics and astronomy. Mercator also apprenticed in the making of scientific instruments under Gas-par a Myrica. In 1534, Mercator established a center for geographic study in Louvain, where he collaborated with Frisius and Myrica to construct his first terrestrial globe two years later. The next year, they collaborated on a celestial globe.
Also in 1537, Mercator published his first map—of Palestine—that he dedicated to Frans Craneveld, a councilor of Emperor Charles V, as was the customary return-in-kind for financial patronage. Other dedications included a 1540 map of Flanders, dedicated to Charles V (for whom he also made two sets of surveying instruments), and a 1541 terrestrial globe, dedicated to M. Nicolas Perrenot de Granvelle, privy councilor of Charles V.
In 1544, Mercator was imprisoned for heresy (he had experienced a religious crisis earlier in life, unable to reconcile the biblical conception of the universe with the Aristotelian one) and held for seven months. He was finally released due to insufficient evidence, after the University of Louvain intervened on his behalf. Soon thereafter, he moved to the Protestant territory of Cleves, where he became the court "cosmographer" for Duke William of Cleves two decades later. In the meanwhile, he constructed another celestial globe in 1551, this one dedicated to Prince-Bishop George of Austria, Bishop of Liege. The next year, he became a lecturer at the University of Duisburg.
In 1554, Mercator published the first modern map of Europe, for which he received an honorarium, presumably from those to whom he dedicated the work: Cardinal Archbishop of Mechelen and Bishop of Arras, Antoine Per-renot de Granvelle, and Phillip II. From 1559 through 1562, he taught mathematics at a grammar school in Duisburg. In 1564, the same year he took up the position of cosmographer under William of Cleves, he published a map of the British Isles.
In 1568 or 1569, Mercator published the work that made the most lasting influence: a world map featuring the "Mercator projection," or the depiction of longitudes and latitudes with straight lines. This map, which increased its distortion as it neared the poles, nevertheless allowed sailors to navigate accurately, as its angles of intersection remain constant across all meridians, as they do in reality. Only four copies of this map, which he dedicated to William, remain in existence. The Mercator projection remains an important nautical tool.
Also in 1569, Mercator commenced work on an "atlas," or a compendium of maps. Merca-tor coined this name after the Greek god who held the earth in his arms, an image that ultimately appeared on the cover of the atlas, which contained incredibly detailed and accurate maps of western and southern Europe. However, it was not until the year after Mercator died—on December 2, 1594, in Duisburg, Germany—that the atlas was published (in an unfinished state) by his son, Rumold, under the title "Atlas—or Cosmographic Meditations on the Structure of the World."
