Galenus, an engraving by the German artist Georg Paul Busch (d. 1756), is a portrait of the prominent Greek physician, surgeon, and philosopher Claudius Galen (ca. 131–ca. 201). Galen treated many powerful individuals in the Roman Empire, including Emperor Marcus Aurelius (161–180) and wrote many works on a variety of topics, including physiology and anatomy, hygiene, and medicines. Galen’s book, De temperamentis (On the Temperaments), served as the basis of medical scholarship for many centuries in the Byzantine Empire and Europe.