The fall of Babylon occurred in 539 BCE, when the Persian Empire conquered the Neo-Babylonian Empire. The success of the Persian campaign, led by Cyrus the Great, brought an end to the reign of the last native dynasty of Mesopotamia and gave the Persians control over the rest of the Fertile Crescent.
Nabonidus, the final Babylonian king and son of the Assyrian priestess Adad-guppi, had ascended to the throne by overthrowing his predecessor Labashi-Marduk in 556.