Andreas Vesalius and De Fabrica

By Michael J. North

A woodcut engraving of Vesalius demonstrating a disection.

Portrait of Andreas Vesalius performing a dissection from his De Humani Corporis Fabrica, 1543
NLM #2295005

This year we commemorate the 500th anniversary of the birth of Andreas Vesalius (1514–1564) who is best known for changing how we do medical research with his groundbreaking book, De Humani Corporis Fabrica Libri Septem (Seven Chapters on the Structure of the Human Body), published in 1543 and generally known as De Fabrica. Among many other things, he placed the study of anatomy at the center of medical education, insisted on physicians performing their own medical research through hands-on investigation, and revolutionized the use of illustration as a teaching tool. While he was long a disciple of Galen, he showed that some of Galen’s writings were flawed, which caused an enormous uproar in the medical world of the 16th century.

Originally from Brussels, Andreas Vesalius attended medical school in Louvain, Paris, and finally Padua, where he became a professor in surgery and anatomy in 1537. Medical research in the early 16th century was mainly a linguistic endeavor, as physicians and humanists sought out the best and least flawed manuscript versions of medieval and ancient medical texts. The only way to discover something unknown about the human body was to find an unexamined text by ancient Greek physicians like second-century Greek physician Galen or the even older writings of Hippocrates, who lived in the fifth century B.C.E. Because so few Europeans knew how to read Galen and Hippocrates in the original Greek, translations into Latin were the primary means of disseminating this newly found information.

Some physicians also sought out texts produced in the middle ages by anatomists like the Italian Mondino dei Luzzi (ca. 1270–1326) and Islamic physicians who produced numerous learned commentaries on the texts of older Greek physicians. Believing that these medieval texts were flawed and mere commentaries on the ancient texts, Vesalius was at first a strong adherent to Galen, and he helped to carefully edit and translate some of the ancient texts for a new Latin translation of Galen’s works in the early 1540s.

Because of this textual approach to medical research, physical investigation and examination of the human body were not considered very important by most physicians. While dissections took place at most medical schools (more frequently in Northern Italy than anywhere else), these were mainly exercises in demonstrating and verifying ancient and medieval texts, not exploring the body itself. The physician/instructor would normally sit on a high chair (cathedra) or stand at a podium with a text of Galen or Mondino, reading aloud as a barber surgeon made incisions in the body for a group of students looking on. Because of this, obvious errors made by Galen—most likely because he had generally only dissected apes, dogs and sheep—generally went unnoticed or were assumed to be anomalies. These dissections were rare and usually did not involve close examination of the cadaver, and Vesalius felt that they were essentially useless: for instance the abdomen was often merely cut open to display the viscera and little else.

A woodcut illustration of large number of saws, knives, probes, scissors and other tools laid out on a table.

Dissection instruments recommended by Andreas Vesalius in his De Humani Corporis Fabrica, 1543
NLM #2295005

When Vesalius arrived in Padua, he began performing dissections on his own and soon started to doubt some of Galen’s anatomical descriptions, which Galen himself admitted were made by consulting older texts and dissecting dogs, sheep, and apes (in particular the Barbary macaque). Differences that Vesalius noticed ranged from the small, such as Galen’s incorrect description of the lumbar vertebral processes, to the fact that the human liver has two lobes rather than five. A major discovery was that humans do not have at the base of their brains a structure called the rete mirabilis, or “miraculous network” of blood vessels, which Galen had observed in the necks of sheep and he claimed suffused the “vital fluid” to the brain, an important part of his theory of human physiology.

Vesalius felt that knowledge of anatomy was essential to the learning and practice of medicine, so he set out to create the ultimate guidebook to the human body. In De Fabrica, he systematically described every bodily structure and backed up all of his descriptions with evidence found in his own dissections of human cadavers rather than with textual evidence from Galen—a revolutionary feat which changed medicine forever. He also commissioned detailed illustrations like none ever published before and touted them as important teaching tools. To reinforce the use of illustrations as teaching tools, he also issued simultaneous to De Fabrica a shorter dissection manual called the Epitome, using many of the same woodblock illustrations.

The dogmatic medical establishment of 16th-century Europe, which slavishly adhered to Galen’s texts, were appalled, and many of them spent a great deal of energy attacking the new “Vesalian anatomy.” Among his most virulent critics was his former professor at the University of Paris, Jacques Dubois (1478–1555), known as “Sylvius,” who published a screed against Vesalius in 1551 entitled, Vaesani Cuisdam Calumniarum in Hippocratis Galenique Rem Anatomicam Depulsio (A Counter-Attack on a Fool’s Slanders Against Hippocrates and Galen). Fear of further criticisms caused Vesalius to pull back from performing other research, and he even burned several manuscripts for other books rather than publish them.

Almost immediately, however, Vesalius’s breakthroughs were acknowledged, and new approaches to medical research, education, and medical illustration began to flourish. In fact, De Fabrica was so popular that plagiarisms of the images and text began to come out almost immediately. One of the most famous examples was Juan Valverde de Amusco’s Historia de la Composicion del Cuerpo Humano, first published in Rome in 1556.

The National Library of Medicine has a large collection of works by and about Andreas Vesalius and his groundbreaking approach. You can see the famous images from De Fabrica here and turn the pages of the book here. To learn more about them, please feel free to contact us at hmdref@mail.nlm.nih.gov.


This article is the second in a series to commemorate the 500th anniversary of the birth of the great anatomist Andreas Vesalius, born on December 31, 1514.

Michael J. North in the incunabulumMichael J. North is the Head of Rare Books and Early Manuscripts in the History of Medicine Division at the National Library of Medicine.