The early history of Cyrus II is somewhat obscure, depending largely upon rather fanciful accounts by Herodotus (Greek historian of the fifth century B.C.E.) and Xenophon (another Greek writer of about a half century later). However, both present Cyrus as the son of the Persian ruler Cambyses by his wife Mandane, the daughter of Astyages, king of the Medes. (Herodotus, I, 107, 108; Xenophon’s Cyropaedia, I, ii, 1)

Xenophon’s account differs somewhat as to details but contains the same basic elements as that of Herodotus. Xenophon describes Cyrus as deeming it nearly impossible to storm Babylon’s mighty walls and then goes on to relate his laying siege to the city, diverting the waters of the Euphrates into trenches and, while the city was in festival celebration, sending his forces up the riverbed past the city walls. The troops under the command of Gobryas and Gadatas caught the guards unawares and gained entrance through the very gates of the palace. In one night “the city was taken and the king slain,” and the Babylonian soldiers occupying the various citadels surrendered the following morning.​—Cyropaedia, VII, v, 33; compare Jer 51:30.