Aelius Galenus or Claudius Galenus (September AD 129 - 199/217; Greek: Ga, Galenos, better known as Galen of Pergamon (modern-day Bergama, Turkey), was a prominent Roman (of Greek ethnicity) physician, surgeon and philosopher. Arguably the most accomplished of all medical researchers of antiquity, Galen contributed greatly to the understanding of numerous scientific disciplines, including anatomy, physiology, pathology, pharmacology, and neurology, as well as philosophy and logic.