Born in the ancient city of Pergamon in 129 CE to a wealthy Greek architect, Galen received a comprehensive education in both medicine and philosophy. He traveled extensively to study diverse medical theories before eventually settling in Rome. In the imperial capital, he rose to great prominence, serving influential citizens and ultimately securing appointments as the personal physician to several Roman emperors.
Galen made extensive contributions to anatomy, physiology, pathology, pharmacology, and neurology. His medical framework was heavily built upon the Hippocratic theory of the four humors: blood, phlegm, yellow bile, and black bile. Because the dissection of human bodies was strictly prohibited in the Roman Empire during his era, Galen conducted anatomical research and vivisections on animals, particularly Barbary apes and pigs, reasoning that their biology closely mirrored that of humans. To supplement this, he urged his students to examine the bodies of deceased gladiators and shipwreck victims.
Viewing himself as both a medical practitioner and a thinker, Galen championed a middle ground between rationalist and empiricist medical sects, a philosophy he articulated in his treatise That the Best Physician Is Also a Philosopher. His voluminous writings remained the undisputed authority in Western medicine for over 1,300 years. His physiological theories were not majorly challenged until the 13th-century circulatory discoveries of Ibn al-Nafis and the landmark 1543 anatomical publications of Andreas Vesalius.
