c. 408-c. 355 B.C.

Greek Astronomer and Mathematician

First to apply mathematics properly in the study of astronomy, Eudoxus also contributed directly to mathematical study with his theory of proportion and his method of exhaustion. In addition, he worked as a medical doctor, and gained renown as a philosopher and political writer. He also wrote a seven-volume description of his travels entitled Circuit of the Earth.

Born in the Greek colony of Cnidus in Asia Minor, Eudoxus came from a long line of physicians, and trained as doctor. By the age of 23, he had moved to Athens to work as a physicians' assistant, and while in the great city attended lectures by Plato (427-347 B.C.) at the latter's Academy. He then returned to Cnidus, where he completed his studies before going to Egypt with another physician.

It was there, at the observatory in...