Fall of Assur

The Fall of Assur occurred when the first city and old capital of the Neo-Assyrian Empire fell to a combined Median-Babylonian alliance. The sack of the city that followed utterly destroyed the city; it would never recover from the destruction.

Background
Ever since the end of Ashurbanipal's reign (and some speculate years before) the Neo-Assyrian Empire was in exposed and critical position; revolts in Babylon and in the Levant coupled with Egyptian and Median invasions proved too much for an empire torn with civil war. In 616 BC, the Babylonians established their de facto independence.

Assault on the city
In 615 BC, the Medians and Babylonians tried to attack Nineveh. However, the Babylonians suffered a serious defeat there, so Nabopolassar took his Babylonian army and instead attacked Assur. The Medians under Cyaxares joined forces with the Babylonians and began a terrible siege of Assur. Much of what was left of the Assyrian army was in Nineveh, unable to assist. Finally, after savage hand-to-hand combat (many skulls and skeletons were later found), it appears that the city was taken in 612 BC.