An alliance formed between external states, such as the Chaldeans, who took advantage of the upheavals in Assyria to take control of much of Babylonia with the aid of the Babylonians themselves. This precipitated the Neo-Babylonian Empire, whose goal was the overthrow of the Neo-Assyrian Empire, seize the capital Nineveh, and transfer the seat of Mesopotamian power to Babylon. Nineveh was not only a political capital, but home to one of the great libraries of Akkadian tablets and a recipient of tribute from across the near east, making it a valuable location to sack.