The rise of Babylon inaugurated a new era in the history of Western Asia. Coincidentally the political power of the Sumerians came to an end. It had been paralysed by the Elamites, who, towards the close of the Dynasty of Isin, successfully overran the southern district and endeavoured to extend their sway over the whole valley. Two Elamite kings, Warad-Sin and his brother Rim-Sin, struggled with the rulers of Babylon for supremacy, and for a time it appeared as if the intruders from the East were to establish themselves permanently as a military aristocracy over Sumer and Akkad. But the Semites were strongly reinforced by new settlers of the same blended stock who swarmed from the land of the Amorites. Once again Arabia was pouring into Syria vast hordes of its surplus population, with the result that ethnic disturbances were constant and widespread. This migration is termed the Canaanitic or Amorite: it flowed into Mesopotamia and across Assyria, while it supplied the "driving power" which secured the ascendancy of the Hammurabi Dynasty at Babylon. Indeed, the ruling family which came into prominence there is believed to have been of Canaanitic origin. Once Babylon became the metropolis it retained its pre-eminence until the end. Many political changes took place during its long and chequered history, but no rival city in the south ever attained to its splendour and greatness. Whether its throne was occupied by Amorite or Kassite, Assyrian or Chaldean, it was invariably found to be the most effective centre of administration for the lower Tigro-Euphrates valley. Some of the Kassite monarchs, however, showed a preference for Nippur. Of its early history little is known. It was overshadowed in turn by Kish and Umma, Lagash and Erech, and may have been little better than a great village when Akkad rose into prominence. Sargon I, the royal gardener, appears to have interested himself in its development, for it was recorded that he cleared its trenches and strengthened its fortifications. The city occupied a strategic position, and probably assumed importance on that account as well as a trading and industrial centre. Considerable wealth had accumulated at Babylon when the Dynasty of Ur reached the zenith of its power. It is recorded that King Dungi plundered its famous "Temple of the High Head", E-sagila, which some identify with the Tower of Babel, so as to secure treasure for Ea's temple at Eridu, which he specially favoured. His vandalistic raid, like that of the Gutium, or men of Kutu, was remembered for long centuries afterwards, and the city god was invoked at the time to cut short his days.