Polycrates, a tyrant of Samos, killed in 522 B. 0. In conjunction with his brothers Pantagnotus and Syloson he seized the sovereignty of Samos. Having assassinated one brother and banished the other, he strengthened the city, enlisted 1,000 archers and manned 100 galleys, and made war with unvarying success upon the neighboring territories. According to Herodotus, Amasis king of Egypt, his friend and ally, wrote to him to sacrifice his most valued possession in order to forestall the misfortunes that Nemesis must have in store for him. Poly crates accordingly threw into the sea a ring of marvellous value; but after some days the ring was found in the stomach of a fish which had been presented to the tyrant. Amasis, more fearful than ever, then broke off his alliance. Grote thinks it more likely that it was Polycrates who broke the alliance in order to cultivate the friendship of Oambyses, to whom he furnished 40 galleys for the invasion of Egypt. He manned these with such of his subjects as he thought to be hostile to himself. They deserted Oambyses, returned to Samos, and attacked Polycrates, but were defeated. They then obtained the assistance of the Spartans and Corinthians, and again attacked Polycrates, but were finally defeated.

Afterward Oroetes, the satrap of Sar-dis, lured him into Magnesia, and he was seized upon his arrival and crucified.