The last of these dynasties preceded a dynasty of kings called Arabian by the copyists of Berosus, and though neither the number of the reigns nor the length of time assigned to the dynasty agrees with what the monuments tell us of the Cassite or Cossæan line of kings, there is no other line which can in any way be identified with the Arabians of the Babylonian historian. The 49 Chaldean kings must, therefore, have reigned before Khammuragas, that is before B.C. 2000-1750. Now an inscription of Nabonidus informs us that Lig-bagas, the first monarch of all Chaldea of whom we know, flourished 700 years anterior to the reign of Khammuragas; he would, therefore, come among the 11 nameless kings of Berosus, supposing any reliance can be placed on the statements of the latter, and about 250 years before the accession of the Chaldean dynasty. But the engraved cylinders and seals of the age of Lig-bagas show that the legend of Izdubar was already popular, and we must accordingly seek a still older period in which to place its origin and attachment to a particular historical event. Hence it may well be that the siege of Erech, the memory of which is preserved in the first book of the Izdubar Epic, was the work of those foreign invaders whom the Babylonian historian has termed Median. Now it is not improbable that the Median dynasty was really Elamite; or at all events belonged to the same race as the primitive inhabitants of Elam. This race was closely allied to the Accadians; and it was spread over the whole range of country which stretched from the southern shores of the Caspian to the Persian Gulf. The Protomedes, as they are sometimes called, were not conquered and supplanted by Aryan invaders from the east till the ninth century B.C. It was in their country that Kharsak-kurra, “the Mountain of the East,” was localized whereon the Accadians and their kinsfolk in Elam and Media believed the ark to have rested after the Flood, and which they regarded as the cradle of their race. It was therefore pre-eminently “the land,” _mada_ in Accadian, and from this _mada_ there is every reason to think the name of Media has been derived. Consequently, the Medians of Berosus, the inhabitants of _mada_ “the land” of the east, need not have been more than one of the many Elamite swarms that from time to time descended into the fertile plains of Babylonia, and not unfrequently obtained a settlement there. Such were the Accadians, or “Highlanders” themselves; such, too, the two Cassite or Cossæan dynasties which we learn from the monuments long held sway over Chaldea. [Illustration: MIGRATION OF EASTERN TRIBE; FROM EARLY BABYLONIAN CYLINDER.]