The Battle of Cunaxa was fought in 401 BC between Cyrus the Younger and his elder brother Arsaces, who had inherited the Persian throne as Artaxerxes II in 404 BC. The great battle of the revolt of Cyrus took place 70 km north of Babylon, at Cunaxa (Greek: Κούναξα), on the left bank of the Euphrates River. The main source is a Greek eyewitness and soldier, Xenophon.