In the 9th century BC, Assyrians based in northern Iraq started a relentless process of expansion that within two centuries would see them controlling most of the ancient Near East. Traditional explanations for the decline of the Neo-Assyrian Empire in the 7th century BC have emphasized the role of military conflict, and especially the destruction of the Assyrian capital, Nineveh, by a coalition of Babylonian and Median forces in 612 BC.