Cyrus, meanwhile, seems to have established contact with Babylon's alienated religious leaders, assuring them of his support for their traditional religious practices. Too late, Nabonidus embraced Marduk, and ordered all statues of the god to be assembled at Babylon to fortify it spiritually.
There are two very different accounts of how Cyrus secured Babylon. One has him defeating the Babylonians at Opis, the former capital of Akkadia, and then destroying that city. Learning this, the city of Sippar surrendered to Cyrus, whereupon Nabonidus fled Babylon and Cyrus made a peaceful entry into the city in October.
The second account is put forward by the Greek historian Herodotus and supported by the books of Daniel and Jeremiah in the Bible—although Daniel incorrectly identifies Darius as king of Persia and Belshazzar as King of Babylon. (The latter was the son of Nabonidus and ruled the city while his father was away on campaign.) This version tells of a great siege during 539–538 BCE.
In it, Cyrus arrived and quickly encircled the city with his army under the walls, cutting off Babylon from assistance. Riding on horseback, Cyrus personally inspected the troop dispositions and concluded that the city could not be taken by direct assault. He then ordered his troops to set up for a siege.
Cyrus was either advised or came up on his own with a stratagem to take the city. He ordered the construction of a circular system of trenches around the city and ditches to be dug sufficient to accommodate the water of the Euphrates River, which bisected Babylon through a break in the city walls. This work went forward into the winter, supervised by Persian engineers. The Euphrates was separated from the ditches by only a simple dam that could be easily opened. The Persians also constructed towers made of palm trees, which led the Babylonians to believe that their enemies intended to starve them out. The authorities in the city were not worried though, as they had gathered sufficient food stocks to last for many years.
Early in 538, Cyrus was ready to unleash his attack, which he timed to coincide with the beginning of an important Babylonian festival. That evening, with the Babylonian rituals underway and the inhabitants distracted, Cyrus ordered the dam broken and the Euphrates diverted. Normally the river was so deep that the breaks in the walls where it flowed through Babylon did not represent a serious threat from outside enemies. When the river was diverted, however, the flow was so low that it was possible for Persian infantry and even cavalry to traverse the newly formed river banks into Babylon itself.
The Persian attack caught the Babylonians by surprise, and the city was soon taken. Cyrus was known for sparing the lives of kings he had defeated, and this may have been the case with Nabonidus. Cyrus, however, ordered that Babylon be destroyed. As the Prophet Jeremiah notes in the Bible (51:29 and 51:37): "And the land shall tremble and sorrow: for every purpose of the Lord shall be performed against Babylon to make the land of Babylon a desolation without an inhabitant. . . . And Babylon shall become heaps, a dwelling place for dragons, an astonishment, and an hissing, without an inhabitant."
Following the reduction of Babylon, Cyrus took Jerusalem. He allowed those Jews of Babylon who wished to do so to return home to Jerusalem, ending the "Babylonian captivity of the Jews." Spencer C. Tucker
Cook, J. M. The Persian Empire. New York: Schocken Books, 1983; Herodotus. The History of Herodotus. Edited by Manuel Komroff. Translated by George Rawlinson. New York: Tudor Publishing Co., 1956; Melegari, Vezio. The Great Military Sieges. New York: Thomas Y. Crowell Co., 1972; Xenophon. Cyropaedia. Trans. Walter Miller. Cambridge, MA: Harvard University Press, 1979.
Spencer C. Tucker