Since the physical characteristics of the ancient Nilotic population, as derived from history and the monuments, coincide in a remarkable manner with the facts derived from anatomical comparison, it becomes in the next place necessary to offer some explanation of these results; or, to show at what periods and under what circumstances several different branches of the Caucasian race were blended into a single nation possessing more or less the characteristics of each, and this again modified in degree by another race wholly different from either. It is in the first place necessary to recur to the fact of the very long occupation of Egypt by successive dynasties of Hykshos or shepherd kings, and that these were not of one but of several nations—Phenicians, Pelasgi, and Scythians; while to these followed, at a long interval, an Ethiopian or Austral-Egyptian dynasty. Each of these great revolutions must have tended in turn to the amalgamation of the Egyptians with other nations; and this result may be referred to three principal epochs, independently of several subordinate ones. THE FIRST EPOCH embraces the dynasty of the Hykshos or shepherd kings, commencing before Christ two thousand and eighty, and having a duration of two hundred and sixty years. It is important, however, to observe, that Josephus quoting Manetho, makes the Hykshos dynasty last five hundred and eleven years; and the learned Baron Bunsen, whose work has not yet appeared, extends it to 1000, beginning B.C. 2514.[120] The shorter period is that of Rosellini; but the longer one is perhaps most consistent with facts, and at least makes room for those various dominations which, in the lists of Manetho, precede the eighteenth dynasty; which last, headed by Amunoph the First, drove out the intrusive kings. During this long period the legitimate sovereigns were exiled into Ethiopia; and it is evident, that had Meroë been any other than a province or dependency of Egypt, it is hardly probable that the Egyptians,—kings, priests, and people,—could have found a safe asylum in that country during the long period of their exile. It is expressly stated by Josephus that the shepherd kings lived at Memphis, “and made both the upper and lower country pay tribute.” It would appear, however, that during the greater part of the Hykshos dynasty, the Egyptians retained possession of the Thebaid: nevertheless the occupation of Lower Egypt by their enemies, must have effectually precluded all communication with other countries excepting Ethiopia, southern Arabia and India; which fact will account for a vast influx of population from those countries, (and consequently from the slave-regions of Africa) into the Upper Nilotic provinces.