Galen, or Claudius Galenus, a famous Greek physician, born at Pergamus, in Illyria, where, after studying in various cities, he settled in 158; subsequently he went to Rome, and eventually became physician to the emperors M. Aurelius, L. Verus, and Severus; of his voluminous writings 83 treatises are still extant, and these treat on a varied array of subjects, philosophical as well as professional; for centuries after his death his works were accepted as authoritative in the matter of medicine (131-201).