There is evidence that Ur-Engur established his rule in Ur, and founded his dynasty in the time of Ur-Ningirsu, the son of Gudea of Lagash. We may therefore place Gudea's accession at about 2450 B.C. This date is some thirteen hundred years later than that assigned to Narâm-Sin by Nabonidus. But the latter, we have already seen, must be reduced, in accordance with evidence furnished by Tello tablets, which are dated in the reigns of the intermediate patesis of Lagash. If we set this interval at one hundred and fifty years,[16] we obtain for Narâm-Sin a date of 2600 B.C., and for Shar-Gani-Sharri one of 2650 B.C. For the later Semitic kings of Kish, headed by Sharru-Gi, one hundred years is not too much to allow;[17] we thus obtain for Sharru-Gi the approximate date of 2750 B.C. It is possible that Manishtusu, King of Kish, was the contemporary of Urukagina of Lagash, but the evidence in favour of the synchronism is not sufficiently strong to justify its acceptance.[18] By placing Urukagina at 2800 B.C., we obtain for Ur-Ninâ an approximate date of 3000 B.C., and for still earlier rulers such as Mesilim, a date rather earlier than this.[19] It is difficult to estimate the age of the early graves, cylinder-seals and tablets found at Fâra, but they cannot be placed at a much later period than 3400 B.C. Thus the age of Sumerian civilization can be traced in Babylonia back to about the middle of the fourth millennium B.C., but not beyond. It must be confessed that this is a reduction in the date usually assigned to the earliest relics that have been recovered of the Sumerian civilization, but its achievements are by no means belittled by the compression of its period of development. It is not suggested that this date marks the beginning of Sumerian culture, for, as we have noted, it is probable that the race was already possessed of a high standard of civilization on their arrival in Babylonia. The invention of cuneiform writing, which was one of their most noteworthy achievements, had already taken place, for the characters in the earliest inscriptions recovered have lost their pictorial form. Assuming the genuineness of the "Blau Monuments," it must be admitted that even on them the characters are in a comparatively advanced stage of development.[20] We may thus put back into a more remote age the origin and early growth of Sumerian culture, which took place at a time when it was not Sumerian.