(c. 600–529 bc), king of Persia (550–529 bc). He was the son of Cambyses I, a descendant of Achaemenes (Hakhamanish) (fl. 681 bc), and a member of the Achaemenid dynasty. When Cyrus became ruler (558 bc) of the Persian district of Anshan, the district was subject to the Medes; in 593 bc he led a rebellion against the Medes that resulted in the capture of King Astyages (r. about 584–c. 550 bc) and the overthrow (550 bc) of the Median Empire. Thereafter Cyrus called himself king of Persia and ruled a territory extending from the Halys River in Asia Minor, eastern border of Lydia, to the Babylonian Empire on the south and east. Babylon, Egypt, Lydia, and the city-state of Sparta in Greece combined to curb the power of Cyrus, but in 546 bc the Persians added Lydia to their realm, and in 539 bc the kingdom of Babylon fell to Cyrus.

The Persian Empire was the most powerful state in the world until its conquest two centuries later by Alexander the Great. Cyrus was an able and merciful ruler. Significant among his deeds was his granting of permission to the Jews to return from their exile in Babylon to their native Israel to rebuild the Temple of Solomon. Cyrus died while leading an expedition against the eastern tribe, the Massagetae, and was succeeded by his son, who became Cambyses II.