The climax in the power of the kings of Ur, the period when they exerted, in fact as well as in name, the sovereignty over all Sumer and Akkad may be fixed approximately at 3000 B.C.How far we shall be able to go beyond that, for the beginnings of this state, must, for the present, remain doubtful, with the chances in favor of a considerably earlier date; and it may be that prior to Ur and Lagash there were dynasties established elsewhere,--at Eridu, perhaps,--the existence of which will be revealed by future discoveries.

An independent state with its seat at Uruk follows upon the culminating period of the glory of Ur, and may be regarded, indeed, as an indication that the rulers of Ur had lost their control over the whole of Southern Babylonia.

Isin, whose site has not yet been determined, but which lay probably to the north of Uruk, was another political center.

Its rulers, so far as we know them, curiously assign the fourth place to the title 'king of Isin,' giving precedence to their control over Nippur, Eridu, and Uruk.

We may conclude from this, that at the time when Isin extended its supremacy, the greater luster attaching to the old towns of Nippur and Uruk, was emphasized by the precedence given to these centers over Isin, although the Isin kings are only 'shepherds' and 'merciful lords' over Nippur and Uruk, and not kings.
At a subsequent period, the kings of Ur appear to have regained the supremacy, which was wrested from them by Isin; and the rulers of the latter acknowledge their dependence upon the kings of Ur.