[1] Descended from an illustrious family from Argos, Polycrates joined the court of the Egyptian monarch Ptolemy IV Philopator, just before his campaign against Antiochus III in 217 BC.
He was of great service in drilling and encouraging the Egyptian troops, and he commanded the cavalry on the left wing at the battle of Raphia, in which Antiochus was defeated, and which secured for Ptolemy the provinces of Coele-Syria, Phoenicia, and Palestine.
Although still young, Polycrates was second to no one in the king's court, says Polybius, and was accordingly appointed by Ptolemy governor of Cyprus.
Following his father's example as an athlete, Polycrates was a winner of the horse races at the Panathenaic Games from 192 to 184 BC, as were his wife and daughters.
[3] This article incorporates text from this source, which is in the public domain: Smith, William (editor); "Polycrates (3)", in Dictionary of Greek and Roman Biography and Mythology, Boston: Little, Brown, and Company.