Galen (130-200), Greek physician, anatomist, physiologist, philosopher, and lexicographer, was probably the most influential physician of all time.

Throughout his life Galen was a prolific writer, producing his first books, Three Commentaries on the Syllogistic Works of Chrysippus, at the age of 13 and his last, Introduction to Dialectics, in the year of his death. His total output has been estimated at more than 2 1/2 million words. Those of his writings which survive make up over half the extant works of ancient medicine.

Various birth dates from 127 to 132 have been suggested, but 130 is generally accepted. Galen was born at Pergamon, Asia Minor, into a well-to-do family with strong scholarly traditions and influenced by the renaissance in Greek culture which had started at the end of the 1st century A.D. This renaissance had led to increasing Hellenization of the Roman world, the adoption of Greek models of learning, and the...