The Neo-Babylonian Empire or Second Babylonian Empire, historically known as the Chaldean Empire, was the last polity ruled by monarchs native to ancient Mesopotamia. Beginning with the coronation of Nabopolassar as the King of Babylon in 626 BC and being firmly established through the fall of the Assyrian Empire in 612 BC, the Neo-Babylonian Empire was conquered by the Achaemenid Persian Empire in 539 BC, marking the collapse of the Chaldean dynasty less than a century after its founding.