The view is certainly attractive, but for that very reason it is necessary to examine carefully the grounds upon which it is based. For deciding the inter-relations of the first three dynasties of the Babylonian King-List, we have certain definite synchronisms established between members of the different dynasties.[30] But between the kings of Babylon and Isin no such synchronism has been furnished by the texts. The theory that the two dynasties were partly contemporaneous rests upon data which admit of more than one interpretation, while additional reasons adduced in its support have since been discredited. The principal fact upon which those who accept the theory rely is that a capture of the city of Isin is commemorated in the formula for the seventeenth year of Sin-muballit, the fifth king of the First Dynasty of Babylon and the father of Hammurabi.[31] Now a capture of the city of Isin by Rîm-Sin, King of Larsa, is also recorded in formulas upon contract-tablets found at Tell Sifr, and that considerable importance was attached locally to this event is attested by the fact that it formed an epoch for dating tablets in that district.[32] The theory necessitates two assumptions, the first to the effect that the date-formulæ of Rîm-Sin and Sin-muballit refer to the same capture of the city; and, secondly, that this event brought the Dynasty of Isin to an end. Granting these hypotheses, the twenty-third year of Damik-ilishu would have coincided with the seventeenth year of Sin-muballit, and the dynasties of Isin and of Babylon would have overlapped for a period of about ninety-nine years. Thus Sumu-abu, the founder of the first Babylonian dynasty, would have been the contemporary of Bûr-Sin II., king of Isin, in the sixth year of whose reign he would have ascended the throne of Babylon. By the acceptance of the theory, not only would the relations of the two dynasties be definitely fixed, but the chronology for the later periods of Sumerian history would be put on a comparatively settled basis, as far back at least as the age of Ur-Engur and Gudea. [Illustration: SPECIMENS OF BABYLONIAN CLAY CONES BEARING VOTIVE INSCRIPTIONS OF GUDEA, PATESI OF SHIRPURLA, OF NUR-ADAD, KING OF LARSA, OF ENANNATUM, AN OFFICIAL IN UR DURING THE REIGN OF GUNGUNU, AND OF UR-ENGUR, KING OF UR.--_Brit. Mus., Nos._ 30089, 30070, 30062, _and_ 30090_; photo, by Messrs. Mansell & Co._]