Cambyses, the second Persian king, succeeded his father Cyrus in 529 B. C, and died in 522. He is probably the Ahasuerus mentioned in Ezra iv. 6-22 as prohibiting the Jews from rebuilding their temple. He completed the annexations of his father in western Asia, and in 525 conquered Egypt, taking its king Psammenitus captive. He then desired to attack Carthage; but the Phoenician fleet, which formed the bulk of his navy, refused to molest their own colony. An army sent to take possession of the temple of Jupiter Amnion perished in the sand, and another army, led by Oambyses himself against the Ethiopians, was reduced by hunger and disease. These disasters seem to have deprived Cam-byses of his senses, and his subsequent conduct was that of a madman. He put his brother Smerdis to death, killed one of his sisters, who was (contrary to Persian law) also his wife, because she mourned for Smerdis, and treated the Egyptians with great cruelty. He gave orders for the destruction of many Egyptian sacred monuments, and slew the god Apis. He ordered Croesus, the ex-monarch of Lydia, to be put to death, and repented immediately that he had done so; but on finding that his officers had saved Croesus, he ordered them to execution for disobedience, though he took the Lydian again into favor.

His eccentricities and long stay in Egypt brought about a revolution in Persia, where Gomates, a Magus, personated Smerdis, and was acknowledged as king. Oambyses received the news in Syria, and was preparing to subdue the impostor, who was supported by the adherents of the Magian religion, when he died, according to Herodotus, from a wound accidentally inflicted by his own sword.