For 1,300 years, medical science relied on a Greek physician who dissected monkeys, not humans.

History · Published 3 October 2026 Swipe more like this →

In short: Galen’s anatomical teachings dominated medicine from the second century until the Renaissance. Because he lacked human specimens, he extrapolated findings from apes and oxen, embedding fundamental errors into medical orthodoxy. It took the bold, hands-on dissections of Andreas Vesalius in 1543 to finally challenge this ancient, flawed foundation.

The history of anatomy is a long transition from speculative philosophy to empirical observation. While ancient Mesopotamians and Egyptians documented organs through sacrificial practices and burial rituals, they often misattributed functions—such as viewing the liver as the seat of the soul. Ancient Greeks later introduced theoretical inquiry, but it was Galen, active in the second century CE, who solidified a system that would persist for over a millennium. Galen’s work, based largely on animal dissection, erroneously described the circulatory system as an open-ended process where blood was consumed as fuel and regenerated by the liver.

During the Middle Ages, anatomical study in Europe largely stagnated, relying on texts rather than direct investigation. However, the Islamic Golden Age saw significant advancements. Scholars like Al-Razi challenged Galenic orthodoxy, while Ibn al-Nafis, often called the father of circulatory physiology, provided the first description of pulmonary circulation. These insights predated European breakthroughs by centuries, yet the European medical establishment remained tethered to Galen’s ancient, unchallenged authority.

The Renaissance marked a turning point. In 1315, Mondino de Luzzi performed the first recorded systematic human dissection in Western Europe at Bologna. By the 16th century, the printing press allowed for the rapid dissemination of new anatomical findings. Andreas Vesalius revolutionized the field with his 1543 work, De Humani Corporis Fabrica. By performing his own dissections and trusting his direct observations over ancient texts, Vesalius exposed that Galen’s descriptions were often based on animal anatomy. This shift transformed anatomy from a lecture-based philosophical exercise into a rigorous, observation-driven discipline, eventually leading to the establishment of anatomical theatres where the public could witness the internal structure of the human body.

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