The Fall of Babylon
Meanwhile to the east, Cyrus, originally king of Anshan, had expanded his power and become king of the Medes and Persians. He had conquered Astyages, the Median king, and captured Ecbatana in 550. He did not immediately turn his attention to Babylonia, but first attacked Lydia and, after an indecisive battle at the Halys River, Sardis fell in 546. Subsequently northern Mesopotamia and territories which had belonged to the Babylonian Empire were taken. The Babylonian army was defeated at Opis on the River Tigris and Sippar was taken. In 539, Cyrus' general Gobryas entered Babylon with his troops, apparently welcomed as liberators, and Nabonidus was taken prisoner.