Andreas Vesalius (also known as Andries van Wesel, 1514-1564) was a pioneering figure in the history of medicine. After studying Artes in Leuven, which he combined with classes at the College Trilingue, he left for Paris in 1533 to study medicine, but the war between France and the Habsburgs forced him to return to Leuven in 1536. There he also published his first work, Ad Regem Almansorem, and performed his first dissections with the faculty's approval. In 1537, Vesalius left for the important medical centre Padua. There he obtained his doctorate in medicine in 1538 and was appointed explicator chirurgiae. His responsibilities included performing dissections for anatomy teaching. Initially, Vesalius followed the theories of Galenus (129-199) and Mondino de' Liuzzi (1270-1326), but by performing dissections on humans and dogs, Vesalius came to the conclusion that Galenus (for whom Vesalius did have great admiration) had only performed dissections on animals, which was not improved by Mondino. This insight caused Vesalius to shift focus to the human body as the ultimate source of knowledge.

This eventually led to the publication of De humani corporis fabrica libri septem in 1543. Because of Vesalius' emphasis on the dissection of the human body, this work, over six hundred pages long and with nearly three hundred detailed illustrations, is considered a turning point in medicine and the beginning of modern medical science. Illustrations were hugely important: hundreds of small images of all possible body parts are scattered throughout the work, but it is the three skeletons at the end of book 1 and the fourteen full-page ‘muscle men’ of book 2 that are particularly impressive. The woodcuts were of exceptional quality and contributed to the success of the work. Thanks to the Fabrica, Vesalius managed to draw attention to the practical aspects of teaching medicine. Whereas previously professors mainly taught ex cathedra from books, Vesalius himself took hold of the dissecting knife, and the touching of bodies was thus no longer left to less-trained barbers and surgeons. By being the first to fully map the entire human body, Vesalius' approach to anatomy went beyond that of his contemporaries, and although not everyone was initially enthusiastic about his work, it opened doors to a renewed focus on hands-on medical education at university level. That Vesalius himself was also aware of the value of his work is also shown by the fact that he dedicated his book to none other than Emperor Charles V. 

A second edition of the Fabrica followed in 1555. Vesalius also made plans for a third edition, as evidenced by his notes in a copy of the second edition. However, that third edition was never published. The 1555 copy with the handwritten notes was purchased by KU Leuven in February 2024, with support from the Flemish Government and the Topstukkenraad and private patronage.

Vesalius remained loyal to the Habsburg court, moving with it to Spain, but he felt less at home there. In 1564, he undertook a trip to Jerusalem, but when the ship had to dock on the Greek island of Zakynthos on the return journey after problems, the very weakened Vesalius died on the spot.