Page:History of Early Iran.pdf/19

mountain valleys of the Zagros. This was the route followed, for example, by some of the Scythians in the seventh century before our era, when they penetrated into Media and Persia and for a time threatened to upset the political arrangement of Western Asia.

On the part of the dwellers in Mesopotamia, there was a constant need to hold in check the highlanders from the Zagros Mountains and the Iranian plateau and to maintain an open trade route with the east. Accordingly, warriors of the lowlands succeeded from time to time in following a few of the arduous paths across the Zagros; then as now, however, for conquest or for commerce, the most frequently traveled route was the Baghdad-Kirmanshah-Hamadan trail. It seemed an irony of fate that this path, favored by the Assyrians, was used by their enemies, the Medes, when they descended from the highlands and subdued the worshipers of Ashur.

On the northeastern frontier, in spite of numerous parallel mountain ranges, entrance to Iran is comparatively unobstructed. Across this frontier, to and from Turkestan and Central Asia, roamed Mousterian man; and the Indo-Iranian peoples who swarmed over it in the second millennium b.c. ultimately brought into being the first of the Indo-Iranian empires, namely, the kingdoms of the Medes and the Persians. In contrast with this frontier the eastern and southeastern borders are almost im-