Vesalius's De Humani Corporis Fabrica, based on his own dissections of executed criminals rather than ancient texts, corrected hundreds of errors inherited from Galen and established modern anatomical study. His willingness to trust direct observation over inherited authority marked a foundational moment in the Scientific Revolution.
Vesalius, a young professor at the University of Padua, broke sharply with medieval medical education, which had relied on lectures read from Galen's ancient texts while a barber-surgeon, considered too lowly for a physician to touch a corpse himself, performed dissections at a distance. Vesalius instead got his own hands bloody, sometimes stealing corpses from gallows at night, and taught by dissecting in front of students himself.
His masterwork, prepared with the Swiss artist Jan van Calcar for its woodcut illustrations, corrected over 200 errors in Galen's descriptions, many of which had come from dissecting animals like Barbary apes rather than humans. The book's illustrations were startlingly beautiful as well as scientifically precise, presenting flayed figures in dramatic poses against landscape backgrounds.
Published in Basel in 1543, the same year Copernicus published his heliocentric theory, the Fabrica represents one of the twin pillars of the early Scientific Revolution: an insistence that nature itself, observed directly, outranked ancient authority. Vesalius reportedly burned his own earlier notes based on Galen after finishing the work, a symbolic break with the past.