The new-comers probably owed their speedy success in Babylonia in great part to the fact that many of the immigrant tribes had already acquired the elements of Babylonian culture. During their previous residence within the sphere of settled civilization they had adopted a way of life and a social organization which differed but little from that of the country into which they came. That they should have immigrated at all in a south-easterly direction, in preference to remaining within their own borders, was doubtless due to racial pressure to which they themselves had been subjected. Canaan was still in a ferment of unrest in consequence of the arrival of fresh nomad tribes within her settled districts, and, while many were doubtless diverted southwards towards the Egyptian border, others pressed northwards into Syria, exerting an outward pressure in their advance. That the West-Semitic invasion of Babylonia differed so essentially from that of Egypt by the Hyksos is to be explained by this fringe of civilized settlements and petty kingdoms, which formed a check upon the nomad hordes behind them and dominated such of them as succeeded in breaking through. In Egypt the damage wrought by the Semitic barbarians was remembered for generations after their expulsion,[25] whereas in Babylonia the invaders succeeded in establishing a dynasty which gave its permanent form to Babylonian civilization. Nîsin, the city in which, as we have seen, we first obtain an indication of the presence of West-Semitic rulers, probably lay in Southern Babylonia, and we may picture the earlier immigrants as descending the course of the Euphrates until they found an opportunity of establishing themselves in the Babylonian plain. The Elamite conquest, which put an end to the dynasty of Ur, and stripped Babylonia of her eastern provinces,[26] afforded Nîsin the opportunity of claiming the hegemony. Ishbi-Ura, the founder of the new dynasty of kings, established his own family upon the throne for nearly a century, and we may probably regard his success in bringing his city to the front as due to the Semitic elements in Southern Babylonia, recently reinforced by fresh accretions from the north-west. The centralization of authority under the later kings of Ur had led to abuses in the administration, and to the revolt of the Elamite provinces; and when an invading army appeared before the capital and carried the king, whom his courtiers had deified, to captivity in Elam,[27] Sumerian prestige received a blow from which it never recovered.