Andreas Vesalius was an anatomist from Flanders. He first studied languages, but in 1531 switched to medicine, becoming professor of surgery and anatomy at the University of Padua at only 23 years of age. In Padua he performed dissections and between 1539 and 1542 he wrote his seven-volume masterpiece De humani corporis fabrica (On the Structure of the Human Body).
Portrait of Andreas Vesalius (1515–1564), engraving by Tavernier after Jacopo Tintoretto (1518–1594), [without date]; source: Smithsonian Institution Libaries, http://www.sil.si.edu/digitalcollections/hst/scientific-identity/fullsize/SIL14-V002-03a.jpg.