Protagoras (prō̇-tăg′ ō̇-rȧs), the earliest of the Greek sophists, was a native of Abdera, born about 481 B. C. The basis of his philosophy is the proposition that “man is the measure of all things.” All his works are lost, and he himself perished at sea (c. 411) while on his way to Sicily to escape a charge of atheism brought against him at Athens.
