Protagoras

Protagoras (c.490–421 B.C.), Greek Sophist, remembered for the maxim “Man is the measure of all things.” A respected figure in Athens, where he spent most of life, he taught rhetoric and the proper conduct of life (“virtue”), and was appointed lawmaker to the Athenian colony of Thurii in 444 B.C. Little is known of his teaching, but he is thought to have been a relativist concerning knowledge and a skeptic about the gods, although he upheld conventional morality.

See also: Sophist.