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)

Herodotus relates that Cyrus revolted against the Median rulership and, because of the defection of Astyages’ troops, was able to gain an easy victory and capture the capital of the Medes, Ecbatana.

Herodotus describes a deep, wide moat encompassing Babylon, relating that numerous bronze (or copper) gates provided entrance through the interior walls along the Euphrates River, which bisected the city. Laying siege to the city, according to Herodotus (I, 191, 192), Cyrus went “drawing off the river by a canal into the lake [the artificial lake said to have been made earlier by Queen Nitocris], which was till now a marsh, he made the stream to sink till its former channel could be forded. When this happened, the Persians who were posted with this intent made their way into Babylon by the channel of the Euphrates, which had now sunk about to the height of the middle of a man’s thigh. Now if the Babylonians had known beforehand or learnt what Cyrus was planning, they would have suffered the Persians to enter the city and brought them to a miserable end; for then they would have shut all the gates that opened on the river and themselves mounted up on to the walls that ran along the river banks, and so caught their enemies as in a trap. But as it was, the Persians were upon them unawares, and by reason of the great size of the city​—so say those who dwell there—​those in the outer parts of it were overcome, yet the dwellers in the middle part knew nothing of it; all this time they were dancing and making merry at a festival . . . till they learnt the truth but too well. [Compare Da 5:1-4, 30; Jer 50:24; 51:31, 32.] Thus was Babylon then for the first time taken.”