This theory was abandoned, however, when it was ascertained that the sphinxes of San had been carved, many centuries before the invasion, for Amenemhait III., a king of the XIIth dynasty. In spite of the facts we possess, the problem therefore still remains unsolved, and the origin of the Hyksos is as mysterious as ever. We gather, however, that the third millennium before our era was repeatedly disturbed by considerable migratory movements. The expeditions far afield of Elamite and Chaldaean princes could not have taken place without seriously perturbing the regions over which they passed. They must have encountered by the way many nomadic or unsettled tribes whom a slight shock would easily displace. An impulse once given, it needed but little to accelerate or increase the movement: a collision with one horde reacted on its neighbours, who either displaced or carried others with them, and the whole multitude, gathering momentum as they went, were precipitated in the direction first given.* * The Hyksos invasion has been regarded as a natural result of the Elamite conquest. A tradition, picked up by Herodotus on his travels, relates that the Phoenicians had originally peopled the eastern and southern shores of the Persian Gulf;* it was also said that Indathyrses, a Scythian king, had victoriously scoured the whole of Asia, and had penetrated as far as Egypt.** Either of these invasions may have been the cause of the Syrian migration. In. comparison with the meagre information which has come down to us under the form of legends, it is provoking to think how much actual fact has been lost, a tithe of which would explain the cause of the movement and the mode of its execution. The least improbable hypothesis is that which attributes the appearance of the Shepherds about the XXIIIrd century B.C., to the arrival in Naharaim of those Khati who subsequently fought so obstinately against the armies both of the Pharaohs and the Ninevite kings. They descended from the mountain region in which the Halys and the Euphrates take their rise, and if the bulk of them proceeded no further than the valleys of the Taurus and the Amanos, some at least must have pushed forward as far as the provinces on the western shores of the Dead Sea. The most adventurous among them, reinforced by the Canaanites and other tribes who had joined them on their southward course, crossed the isthmus of Suez, and finding a people weakened by discord, experienced no difficulty in replacing the native dynasties by their own barbarian chiefs.*** * It was to the exodus of this race, in the last analysis, that the invasion of the shepherds may be attributed