The Elamite had seen his opportunity in the continual conflicts which were taking place between the two rival cities of Sumer. In their contest for the hegemony Larsa had proved herself successful for a time, but she was still the weaker city and doubtless more exposed to attack from across the Tigris. Hence her selection by Kudur-Mabuk as a basis for his attempt on the country as a whole. He himself retained his position in Elam as the _Adda_ of Emutbal; but he installed his two sons, Warad-Sin and Rîm-Sin, successively upon the throne of Larsa, and encouraged them to attack Nîsin and to lay claim to the rule of Sumer and Akkad. But the success which attended their efforts soon brought Babylon upon the scene, and we have the curious spectacle of a three-cornered contest, in which Nîsin is at war with Elam, while Babylon is at war in turn with both. That Sin-muballit, the son of Apil-Sin, did not combine with Nîsin to expel the invader from Babylonian soil, may have played at first into the hands of the Elamites. But it is not to be forgotten that the Western Semites of Babylon were still a conquering aristocracy, and their sympathies were far from being involved in the fate of any part of Sumer. Both Elam and Babylon must have foreseen that the capture of Nîsin would prove a decisive advantage to the victor, and each was content to see her weakened in the hope of ultimate success. When Rîm-Sin actually proved the victor in the long struggle, and Larsa under his regis inherited the traditions as well as the material resources of the Nîsin Dynasty, the three-cornered contest was reduced to a duel between Babylon and a more powerful Larsa. Then for a generation there ensued a fierce struggle between the two invading races, Elam and the Western Semites, for the possession of the country; and the fact that Hammurabi, Sin-muballit's son, should have emerged victorious, was a justification in full of his father's policy of avoiding any alliance with the south. The Western Semites proved themselves in the end strong enough to overcome the conqueror of Nîsin, and thereby they were left in undisputed possession of the whole of Babylonia.