Person: Mercator, Gerard
Gerardus Mercator was a Flemish map-maker and geographer who is best known for the map projection which bears his name.
Mathematical Profile (Excerpt):
- It was in the hospice of St Johann in Rupelmonde, where Gisbert was a priest, that Gerard was born.
- For the first five years of his life Gerard and his parents lived in difficult conditions in Gangelt.
- Hubert had leased a house in Rupelmonde in 1511, shortly before Gerard's birth, and in 1518 they journeyed from Gangelt to Rupelmonde to begin a new life.
- Gisbert wanted the very best education possible for Gerard so in about 1527 he sent him to be educated with the Brethren of the Common Life in 'sHertogenbosch in the Netherlands.
- As a new name he chose Mercator, the Latin for 'merchant' and gave himself the full name of Gerardus Mercator de Rupelmonde.
- On 29 August 1530 Mercator matriculated at the University of Louvain, taking the course in the humanities and philosophy.
- After graduating, Mercator began to have serious worries on how to reconcile the account of the origin of the universe given in the Bible with that given by Aristotle.
- Mercator returned to Louvain in 1534 where he now studied mathematics under Gemma Frisius.
- However, not having any background in the subject, Mercator soon found that the mathematics courses beyond him.
- Realising that Mercator wanted to learn mathematics to apply it to cosmography, Gemma Frisius gave him advice on the best route into learning the mathematics he needed to know, giving him books to study at home.
- Once put on the right path by Gemma Frisius, Mercator quickly progressed in understanding and enjoyment of mathematics.
- Mercator learnt to be an engraver and instrument maker at this time from Gaspard Van der Heyden (also known as Gaspar à Myrica).
- However at this time Mercator was not only was learning, he was also teaching.
- In 1535-1536 Mercator, working in Louvain with Van der Heyden and with Gemma Frisius, constructed a terrestrial globe.
- The geographical work was mainly due to Gemma Frisius while Mercator's role was that of an engraver.
- In 1537 Mercator, working with Van der Heyden and with Gemma Frisius, constructed a globe of the stars.
- The first map of the world to be produced by Mercator used a projection due to Oronce Fine and appeared in 1538.
- It suggested an independent Flanders and Mercator's map was commissioned to correct this impression.
- Mercator produced a map of high accuracy using data from a survey of Flanders carried out using the method of triangulation described by Gemma Frisius.
- Mercator had a long term plan of producing a world map by producing individual maps of the different regions.
- Mercator realised the reason for some of the incorrect data; sailors assumed that following a particular compass course would have them travel in a straight line whereas this was untrue.
- He realised that a ship sailing towards the same point of the compass would follow a curve called a loxodrome (also called a rhumb line or spherical helix), a curve recently studied by Pedro Nunes who was a mathematician greatly admired by Mercator.
- Mercator was arrested in February 1544 and charged with heresy.
- Nothing was found to connect Mercator with the others 'heretics' even after they had been tortured.
- Mercator's house was searched and his belongings confiscated but nothing incriminating was found to show that he was anything other than a good Roman Catholic.
- John Dee arrived in Louvain in 1548 and quickly became friends with Mercator.
- During this time Mercator worked on a celestial globe of the same size as his terrestrial globe of 1541 which he completed in 1551.
- In 1552 Mercator moved to Duisburg where he opened a cartographic workshop.
- In Duisburg Mercator completed his project to produce a new map of Europe by October 1554.
- This re-established Mercator as the leading European map maker and, as well as praise for its scholarly value, the map had considerable commercial value.
- When plans for the university were scrapped in 1562, Mercator ended his teaching duties at the school handing them over to his second son.
- Mercator was appointed Court Cosmographer to Duke Wilhelm of Cleve, also in 1564.
- The 'Mercator projection' had the property that lines of longitude, latitude and rhomb lines all appeared as straight lines on the map.
- Mercator published corrected and updated versions of Ptolemy's maps in 1578 as the first part of his 'atlas'.
- Although the project was never completed Mercator did publish a further series in 1589 including maps to the Balkans (then called Sclavonia) and Greece.
- On 5 May 1590 Mercator had a stroke which left his left side paralysed.
- Mercator's break from the methods of Ptolemy was as important for geography as was Copernicus for astronomy.
Born 5 March 1512, Rupelmonde, Burgundian Netherlands (now Belgium). Died 2 December 1594, Duisburg, Duchy of Cleves (now Germany).
View full biography at MacTutor
Tags relevant for this person:
Origin Belgium
Thank you to the contributors under CC BY-SA 4.0! 
- Github:
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- non-Github:
- @J-J-O'Connor
- @E-F-Robertson
References
Adapted from other CC BY-SA 4.0 Sources:
- O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive
