The Political Approach to the Classical World 33 elementsthe native Subarean population, the conquering Khurrians, and the ruling caste who introduced Indo-European words into the language and called their own gods to witness their treaties with foreign Powers. This southward movement of peoples into Asia Minor, Subartu, and Mesopotamia naturally caused a displacement of the populations already settled in the Fertile Crescent, and it drove down into Syria and Palestine the dreaded Hyksos, the Shepherd Kings. Their identity is a matter of debate; perhaps it is safest to assume that they were a mixed race, speaking a Semitic language and worshipping the storm-god Sutekh. From the northern invaders they had learnt the use of the chariot; their fortresses were massive structures surrounded by a smooth sloping glacis which made approach difficult. Through Palestine they came, conquering and destroying, and into Egypt, where the Thirteenth Dynasty was maintaining a feeble hold and no leader was found strong enough to unite the country in resist- ance. Again Egypt split into local principalities, and now, for the first time in her history, she suffered the indignities of con- quest by foreigners. At first destroyers, the later Hyksos kings did their best, it seems, to adapt themselves to Egyptian ways; they adopted hieroglyphic writing and identified their storm- god with the Egyptian Set, and they forbore to interfere with their subjects more than was necessary. But the Egyptians never forgot that they were foreigners, and centuries later their name was still anathema. At last a line of deliverers arose, again in the city of Thebes. The last princes of the Seventeenth Dynasty fought against the foreigners and gradually, step by step, drove them out of Egypt. Not content with the liberation of their country, the first kings of the Eighteenth Dynasty pressed on into Palestine, and-so the Egyptians, carried northward by the impetus of their pursuit, found themselves embarking on a career of conquest in Asia such as they had never before attempted.