Cyrus (II) the Great

King of Persia 559–530 BC and founder of the Achaemenid Persian Empire. The son of the vassal king of Persia and of a daughter of his Median overlord Astyages, Cyrus rebelled in about 550 BC with the help of mutiny in the Median army and replaced the Median Empire with a Persian one. In 547 BC he defeated Croesus of Lydia at Pteria and Sardis, conquering Asia Minor. In 539 BC he captured Babylon from Nabu-naid (Nabonidus) the Chaldaean, formerly his ally against the Medes, and extended his frontiers to the borders of Egypt. He was killed while campaigning in Central Asia, and was succeeded by his son Cambyses II.

Cyrus probably founded the Immortals and spear-bearers, and may have been the first to organize an effective force of Persian cavalry. The historian Xenophon gave an idealized portrait of him in his book Cyropaedeiq, and he became a model of the ideal ruler for the Greeks.