Danke’,
As I recall though, the Assyrians overtook Babylon and captured the city fairly quickly?
The Assyrians conquered Mesopotamia a number of times, and lost control one way or other each time. One uprising was actually by the Assyrian viceroy and brother of the Assyrian king. :’) What we know as the Babylonian Empire (often called the Neo-Babylonian Empire, and it is discussed in the Old Testament) began after the destruction of Nineveh.