Gerardus Mercator


Gerhard Mercator († December 2, 1594 in Duisburg, United Duchies of Jülich-Kleve-Berg) was a geographer and cartographer who was considered the Ptolemy of his time during his lifetime and was famous as far away as the Arab-Islamic world. His real name was Gheert Cremer (Latinized Gerardus Mercator (“merchant”), German also Gerhard Krämer).

Known today primarily as a cartographer and globe maker, Mercator was also important in the 16th century as a cosmographer, theologian, and philosopher, and set standards as a scribe.

Years of life in Flanders

Mercator was born the seventh child of Hubert Cremer and his wife Emerentia in Rupelmonde, southwest of Antwerp. Until the age of six, he spent his childhood in Gangelt, 120 km away, where his father was a shoemaker. In 1518 the family moved entirely to Rupelmonde and after the death of his father in 1526, Gerhard was educated by the Brothers of the Common Life in Herzogenbusch with the encouragement of his uncle Gisbert, who was a clergyman in Rupelmonde. Here, among others, Georgius Macropedius was his teacher.

From 1530, Gerhard studied at the University of Louvain under Gemma Frisius, was awarded the degree of Magister artium in 1532, and then pursued private studies in theology, philosophy, and mathematics, especially in their practical applications (maps, globes, and instruments). From 1534 to 1537, Mercator was a collaborator with Gemma Frisius in the creation of his terrestrial and celestial globes.

In 1536 he married Barbara Schellekens, who gave birth to their first son Arnold in 1537. In 1537 he created a first map Amplissima Terrae Sanctae descriptio ad utriusque Testamenti intelligentiam. In 1538 he created his first map of the world. In the same year his first daughter was born, who was christened Emerance after Mercator”s mother. In 1539 followed the second daughter Dorothéa.

Also in 1539, Mercator published a map of Flanders, which brought him the attention of the king. In 1541, Mercator brought out his first globe, which sold in large numbers for decades. In 1540 and 1541, two sons were born, Bartholomew (1540-1568) and Rumold. In 1542 followed as the sixth and last child the daughter Katharina.

Whether Mercator earned a doctorate in theology is questionable. In 1544, he was arrested for “Lutherey” (i.e., being a follower of Martin Luther”s Reformation) and imprisoned for many months. During this time, Philipp Melanchthon”s Initia Doctrinae Physicae (1549), a major work in the natural sciences, was published and may have had a great influence on Mercator. The correspondence with Melanchthon, which has only recently been discovered, has not yet been evaluated.

In 1551, Mercator made the first complementary celestial globe to his 1541 globe. From then on, these globes were mostly sold in pairs, of which at least 22 still exist.

Move to Duisburg

In 1551, William the Rich invited him to become professor of cosmography at the newly founded University of Duisburg. Mercator accepted the offer and moved to Duisburg in 1552, where he lived in a house on Oberstraße; whether reasons of faith played a decisive role is disputed. In any case, he lived safe from hostility in the city in the Duchy of Cleves, which was characterized by religious tolerance.

From 1559 to 1562, he was a teacher of mathematics and cosmography at the newly founded Duisburg Academic Gymnasium, today”s Landfermann Gymnasium. One of Mercator”s students from 1562 was Johannes Corputius, who in 1566 produced the exceptionally accurate city view of Duisburg named after him, the Plan of Corputius. The foundation of the university did not come about during Mercator”s lifetime, although the duke had received papal permission in 1564 and also the imperial privilege to found it in 1566.

The big world map

With his great world map of 1569 (Nova et aucta orbis terrae descriptio ad usum navigantium), Mercator achieved world fame. Possibly inspired by Erhard Etzlaub, he developed a projection that is still important today because of its angular accuracy for navigation (and aviation), which became known as the “Mercator projection”.According to John Vermeulen, Mercator collaborated with his contemporary Abraham Ortelius.

In the 1570s, Mercator published theological writings, most of which were unknown, or at least unappreciated, until recently. He was concerned with the theology of the Swiss Reformed. He may also have been inspired by the so-called “Christian Physics” of Lambertus Danaeus, a disciple of Calvin.

Mercator”s theologically influenced world history Chronologia appeared at about the same time as the world map. Hoc est temporum demonstratio exactissima, ab initio mundi usque ad annum Domini MDLXVIII (1568). Further cartographic work was followed in 1590 by the Commentary on the Epistle to the Romans, which so far exists only as a manuscript in Leiden, in which he worked out the theological-systematic foundations for his cosmography. The Chronologia was listed as a forbidden book by the Catholic Church in the annex to the Council of Trent in 1563.

The main work

Shortly before his death, Mercator completed the main work, the cosmography Atlas, sive Cosmographicae Meditationes de Fabrica Mundi et fabricati figura, which was published posthumously in 1595 by Mercator”s son Rumold. So far, it is mainly the maps that have been taken note of, and occasionally these have even appeared without the text. Particularly noteworthy is the Christological orientation, which is fundamentally different from the medieval cosmographies up to Sebastian Münster.

The atlas was also placed on the index by decree of the Roman Catholic Congregation for the Doctrine of the Faith on August 7, 1603.

Mercator died in 1594 as a respected and wealthy man. His grave in the Salvatorkirche in Duisburg has disappeared, only his magnificent epitaph is still there.

Mercator saw himself more as a scientific cosmographer than as someone who had to earn a living by making and selling maps. His production was quite extensive: we know twelve pairs of globes (heaven and earth), five wall maps, many maps of regions, world maps, as well as a chronology (with gospel harmony) and cosmography. Many of his works are now exhibited in the treasury of the Cultural and Urban History Museum of the City of Duisburg.


From the Duisburg period we know only four wall maps:

This last map can rightly be called Mercator”s masterpiece. It is the first world map to use a true-angle projection (Mercator projection).


After the edition of the world map, Mercator shifted more and more to the production of a cosmography. Mercator had big plans: a huge cosmographic work about the creation, its origin and its history.

He wrote the first ideas for it in 1569 in the introduction to his Chronologia. The cosmography would consist of five parts:

Mercator”s scientific attitude became his fate. Again and again he postponed the publication of his work in the hope of new information. The cartographic part of his cosmography was therefore only partially completed.

First was made his Ptolemy edition of 1578. Mercator saw this edition merely as a representation of the world according to the ideas of the classical authors. The 28 Ptolemaic maps have never been included in any other atlas, while they were republished as late as 1730.

It was not until 1585, fifteen years after the edition of the Theatrum, that Mercator came up with an unfinished edition of his ”modern geography”.

The map book contains 51 maps: 16 of France, nine of the Netherlands and 26 of Germany. Of these countries he had the most reliable descriptions. Each part has its own title page: Galliae Tabulae Geographicae, Belgii Inferioris Geographicae Tabulae and Germaniae tabulae geographicae. The whole did not have a title yet.

In 1589, 22 maps of Southeastern Europe, Italiae, Sclavoniae et Graeciae tabulae geographicae followed. Mercator unfortunately did not have the opportunity to expand his Tabulae Geographicae to a real world atlas with a volume of about 120 maps, according to his original plan.

A year after his death, his son Rumold Mercator published a supplement with 34 maps. This contains 29 maps engraved by Gerhard Mercator of the missing parts of Europe (Iceland, the British Isles, and the northern and eastern European countries).


Rumold”s “complete edition” has its own title page and preface. The title is Atlas sive Cosmographicae Meditationes de Fabrica Mundi et Fabricati Figura (Atlas or Cosmographic Meditations on the Creation of the World and the Form of Creation).

Mercator explained the choice of the title Atlas in an introduction. According to this, the name is derived from the mythical king and first astrologer Atlas of Mauritania, who, according to Mercator”s account and the accompanying genealogical table, was the Atlas of Greek mythology. Mercator refers to the stories of Diodorus.

Atlas is depicted on the title copperplate of Mercator”s Atlas with a celestial globe and an terrestrial globe.

The work begins with a biography of Gerardus Mercator, written by the Duisburg councilman Walter Ghim, followed by the atlas mythology. The first part is Mercator”s work on the creation Mundi Creatione et Fabrica Liber. The 107 maps form the second part.

Lettering art

It is characteristic for his understanding as a scientist of the Renaissance that the vividness of his thinking was permeated by a high demand on the aesthetics of representation. In the history of the development of writing, Mercator also occupies an important place as a master of writing.

In 1540, he published a guide to writing Italian cursive: Literarum latinarum, quas Italicas, cursoriasque vocant scribendarum ratio. Thus, he was not only one of the first scribal artists north of the Alps to popularize this space-saving and clear Latin script type over the Gothic script in the context of a scribal master book, but he was also the first to use this cursive for inscribing maps.

His instructions (52 pages) were initially still cut in wood and were reprinted in the same year as well as in 1549, 1550, 1556 and 1557.The later use of copperplate engraving allowed the elegant design of this typeface to be better appreciated. Mercator thus set aesthetic standards for the lettering of maps and shaped the map style for the following two hundred years.

The University of Duisburg, founded in 1655, closed in 1818. The comprehensive university of Duisburg, newly founded in 1972, had the name “Gerhard Mercator University” since 1994 until it merged with the University of Essen in 2003 to form the new University of Duisburg-Essen. The Mercator School of Management exists at the Duisburg campus.

Furthermore, the Duisburg Mercator High School, a Berlin elementary school, an event and congress center (Mercatorhalle), a shopping center in Duisburg-Meiderich and a Moers vocational college are named after him, as is the southern ring road Mercatorstraße

The Mercator Society Duisburg, an association for history and local history, has also existed since 1950.

The Mercator plaque for special services, particularly in the scientific or artistic field, is awarded by the City of Duisburg at irregular intervals. Previous recipients have included founding rectors of Duisburg University, heads of cultural departments and music directors, as well as the actor Hans Caninenberg and the painter Heinz Trökes.

In addition, there is the Mercator Foundation, founded by an entrepreneurial family from Duisburg. It is one of the largest foundations in Germany and provides funding in particular in the areas of integration, climate change and cultural education.

The lunar crater Mercator was named after him in 1935, and the asteroid (4798) Mercator has borne his name since 1991.

A monument was also erected in his honor in Gangelt, where Mercator grew up from 1512 to 1518. The so-called Mercator Point is located at the point of confluence of the 6th degree of longitude and the 51st degree of latitude, on the northern edge of the main town of the municipality of Gangelt.

About Mercator

Works online



  1. Gerhard Mercator
  2. Gerardus Mercator