Date of birth unknown; died circa 523 or 522 B.C. Ancient Greek tyrant of the island of Samos from circa 540.

During Polycrates’ reign, the polis of Samos became unified. As the owner of a bronze workshop, Polycrates pursued external and internal policies in the interests of the merchant and craftsman strata of the population. He initiated the minting of coins by the government and large-scale construction projects. He created a merchant marine fleet and a land army, fought with the cities of Asia Minor and the islands of the Aegean Sea over trade routes, and concluded treaties with Athens, Naxos, and Cyrenaica. The policies of Polycrates met with active resistance from the clan aristocracy, who joined with Sparta and Corinth to mount a rebellion against him. Polycrates was killed by order of the Achaemenids, who feared the increased strength of Samos.