Tyrant of Samos (c. 535-515 B.C.).. Having won popularity by donations to poorer citizens, he took advantage of a festival of Hera, which was being celebrated outside the walls, to make himself master of the city (about 535 B.C.).
After getting rid of his brothers Pantagnotus and Syloson, who had at first shared his power, he established a despotism which is of great importance in the history of the island. Realizing clearly the value of sea-power for a Greek state, he equipped a fleet of zoo ships, and so became master of the Aegean basin. This ascendancy he abused by numerous acts of piracy which made him notorious throughout Greece; but his real purpose in building his navy was to become lord of all the islands of the archipelago and the mainland towns of Ionia. The details of his conquests are uncertain, but it is known that in the Cyclades he maintained an alliance with the tyrant Lygdamis of Naxos, and curried favour with the Delian Apollo by dedicating to, him the island of Rheneia. He also encountered and heavily defeated a coalition of two great naval powers of the Asiatic coast, Miletus and Lesbos. Doubtless with the object of expanding the flourishing foreign trade of Samos, he entered into alliance with Amasis, king of Egypt, who, according to Herodotus, renounced his ally because he feared that the gods, in envy of Polycrates' excessive good fortune, would bring ruin upon him and his allies. It is more probable that the breach of the compact was due to Polycrates, for when Cambyses of Persia invaded Egypt (525) the Samian tyrant offered to support him with a naval contingent. This squadron never reached Egypt, for the crews, composed as they were of Polycrates' political enemies, suspecting that Cambyses was under agreement to slay them, put back to Samos and attacked their master. After a defeat by sea, Polycrates repelled an assault upon the walls, and subsequently withstood a siege by a joint armament of Spartans and Corinthians assembled to aid the rebels. He maintained his ascendancy until about 515, when Oroetes, the Persian governor of Lydia, who had been reproached for his failure to reduce Samos by force, lured him to the mainland by false promises of gain and put him to death by crucifixion.
Beside the political and commercial pre-eminence which he conferred upon Samos, Polycrates adorned the city with public works on a large scale - an aqueduct, a mole and a temple of Hera (see SAMOS; AQUEDUCTS). The splendour of his palace is attested by the proposal of the Roman emperor Caligula to rebuild it. Foreign artists worked for him at high wages; from Athens he brought Democedes, the greatest physician of the age, at an exceptional salary. He was also a patron of letters: he collected a library and lived on terms of intimate friendship with the poet Anacreon, whose verses were full of references to his patron. The philosopher Pythagoras, however, quitted Samos in order to escape his tyranny. (M. O. B. C.)