Cyrus the Great. Born about 590 B.C. Founder of the Persian Empire. Cyrus was the son of Cambyses and Mandane, daughter of Astyages, king of Media. His early history is probably mythical. In 549 B.C. Cyrus excited the Persians against the Medes, defeated Astyages, and usurped his throne. He subsequently conquered Lydia and Babylon, and marched against the Massegatae, governed by Queen Tomyris, by whom Cyrus was defeated and slain, 529 B.C.