The Fall of Babylon denotes the end of the Neo-Babylonian Empire after it was conquered by the Achaemenid Empire in 539 BCE. Nabonidus (Nabû-na'id, 556–539 BCE), son of the Assyrian priestess Adda-Guppi, came to the throne in 556 BCE, after overthrowing the young king Labashi-Marduk. For long periods he entrusted rule to his son, prince and coregent Belshazzar, who was a capable soldier, but a poor politician. All of this left him somewhat unpopular with many of his subjects, particularly the priesthood and the military class.

To the east, the Achaemenid Empire had been growing in strength. In October 539 BCE, Cyrus the Great entered Babylonia in peace without being engaged in any battle. Babylonia was thereafter incorporated into the Persian Achaemenid realm as a satrapy.

The Hebrew Bible also unreservedly praises Cyrus for his actions in the conquest of Babylon, referring to him as Yahweh's anointed. He is credited with freeing the people of Judah from their exile and with authorizing the reconstruction of much of Jerusalem, including the Second Temple.