The name of three different empires dating from about 2000-600 BC, the city-state of Assur, and the people inhabiting this northeastern area of Mesopotamia. Originally Semitic nomads in northern Mesopotamia, they finally settled around Assur and accepted its tutelary god as their own. After the fall of the 3rd Dynasty of Ur (2004 BC), Assyria seems to have become an independent city-state and important as middleman in international trade. In its period of greatness, 883-612 BC, there was continuous war in Assyria to keep the empire's lands which at their widest extended from the Nile to near the Caspian, and from Cilicia to the Persian Gulf (Egypt, much of the area to the west as far as the Mediterranean, Elam to the east and parts of Anatolia to the north). Its greatest kings were all warriors, Ashurnasirpal II, Shalmaneser III, Tiglathpileser III, Sargon II, Sennacherib, and Ashurbanipal, who made the name of Assyria feared throughout the ancient East through their military skill and brutality. The main achievements in Assyria, outside warfare, were in architecture and sculpture, particularly the protective winged bulls, etc., which guarded all palace entrances, and the magnificent reliefs of battles, hunts, and military processions which adorned the walls. Assurnasirpal II (833-859 BC) transferred the center of government to Calah (Nimrud). The fortunes of the empire rose and fell under the kings of the 9th-7th centuries: Assurbanipal (668-627 BC) reconquered Egypt, but in 614 BC the empire fell when the Medes invaded Assyria, captured Calah, and destroyed Assur.