In 539 BCE, Cyrus invaded Babylonia. Historical reconstruction of the fall of Babylon to Persia has been problematic, due to the inconsistencies between the various source documents. Both the Babylonian Chronicles and the Cyrus Cylinder describe Babylon being taken "without battle", whereas the Greek historians Herodotus and XenophonHistories I.191; Cyropaedia VI.5.15–16; . report that the city was besieged. The biblical Book of Daniel notes that the king was killed.
