The area in which Mosul lies was an integral part of Assyria from as early as the 25th century BC. After the Akkadian Empire (2335–2154 BC), which united all of the peoples of Mesopotamia under one rule, Mosul again became a continuous part of Assyria proper from circa 2050 BC through to the fall of the Neo-Assyrian Empire between 612 and 599 BC. Mosul remained within the geopolitical province of Assyria for a further thirteen centuries (as a part of Achaemenid Assyria, Seleucid Syria, Roman Assyria and Sasanian Asōristān) until the early Muslim conquests of the mid-7th century. After the Muslim conquests, the region saw a gradual influx of Muslim Arab, Kurdish and Turkic peoples, although the indigenous Assyrians continue to use the name "Athura" for the ecclesiastical province.