Eudoxus of Cnidus

Eudoxus of Cnidus was an ancient Greek astronomer, mathematician, physician and lawmaker, born and died in Cnidus on the southwest coast of Anatolia. His dates are uncertain: older reckoning gives 408 to 355 BC, while modern scholars prefer a birth year of about 390 BC. He studied mathematics with Archytas and medicine with Philiston, was a student of Plato, trained in Egypt, and gathered students of his own at Cyzicus before returning to Athens and later home, where he built an observatory. His fame in astronomy rests on the introduction of concentric spheres to explain the motion of the planets, and his work on proportions allowed a rigorous treatment of continuous quantities and later inspired Richard Dedekind's work on the real numbers. Some consider him the greatest of the classical Greek mathematicians. He was probably the source of most of book V of Euclid's Elements and he developed the method of exhaustion, a precursor of the integral calculus. All of his original works are lost.