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. This so-called second dynasty of Ur includes Nippur. The kings are proud of calling themselves the guardians of the temple of Bel in Nippur, nominated to the office by the god himself, and reviving an old title of the kings of Agade, style themselves also 'king of the four regions.' Another change in the political horoscope is reflected in the subjection of Ur to a district whose center was Larsa, not far from Ur, and represented by the mound Senkereh. There are two kings, Nur-Ramman (_i.e._, light of Ramman) and Sin-iddina (_i.e._, Sin judges), who call themselves guardians of Ur and kings of Larsa, showing that the center of this principality was Larsa, with Ur as a dependent district. That these rulers take up the dominion once held by the kings of Ur is further manifest in the additional title that they give to themselves, as 'kings of Sumer and Akkad,' whereas the omission of the title 'king of the four regions' indicates apparently the exclusion of Agade and Nippur; and with these, probably North Babylonia in general, from their supremacy. The power of Larsa receives a fatal check through the invasion of Babylonia by the Elamites (_c._ 2350 B.C.). These variations in official titles are a reflection of the natural rivalry existing between the various Babylonian states, which led to frequent shiftings in the political situation. Beyond this, the inscriptions of these old Babylonian rulers, being ordinarily commemorative of the dedication to a deity, of some temple or other construction--notably canals--or of some votive offering, a cone or tablet, unfortunately tell us little of the events of the time. Pending the discovery of more complete annals, we must content ourselves with the general indications of the civilization that prevailed, and of the relations in which the principalities stood to one another, and with more or less doubtful reconstructions of the sequence in the dynasties. In all of this period, however, the division between North and South Babylonia was kept tolerably distinct, even though occasionally, and for a certain period, a North Babylonian city, like that of Agade and Nippur, extended its jurisdiction over a section bordering on the south and _vice versa_. It remained for a great conqueror, Hammurabi, the sixth king of a dynasty having its seat in the city of Babylon itself, who about the year 2300 B.C. succeeded in uniting North and South Babylonia under one rule. With him, therefore, a new epoch in the history of the Euphrates Valley begins. Henceforth the supremacy of the city of Babylon remains undisputed, and the other ancient centers, losing their political importance, retain their significance only by virtue of the sanctuaries existing there, to which pilgrimages continued