Until the beginning of the nineteenth century A.D. from the earliest times with which we can come into contact through any human record, this high-road (not the only one, but the chief one) must have been trodden by the feet of thousands of weary pilgrims, captives, emigrants, merchants, or fighting men--an intermittent tide of humanity exceeding in volume any host known to modern days--bringing East into touch with the West to an extent which we can hardly appreciate. It may be said that the straightest road to Baktria did not lie through Ecbatana. It did not; but independently of the fact that Ecbatana was a city of great defensive capacity, and of reasons both political and military which would have impelled Darius to take that route, we shall find if we examine the latest Survey of India map of Western Persia that the geographical distribution of hill and valley make it the easiest, if not the shortest, route. The configuration of Western Persia, like that of Makran and Southern Baluchistan extending to our own north-west frontier, mainly consists of long lines of narrow ridges curving in lines parallel to the coast, rocky and mostly impassable to travellers crossing their difficult ridge and furrow formation transversely, but presenting curiously easy and open roads along the narrow lateral valleys. Ecbatana once stood where the modern Hamadan now stands. The road from Arbil (or Erbil) that carries most traffic follows this trough formation to Kermanshah and then bends north-eastward to Hamadan. From Hamadan to Rhagai and the Caspian gates, which was the route followed by Darius in his flight from Ecbatana, the road was clearly coincident with the present telegraph line to Tehran from Hamadan, which strikes into the great post route eastward to Mashad and Herat, one of the straightest and most uniformly level roads in all Asia. It must always have been so. Remarkable physical changes have occurred in Asia during these twenty-five centuries, but nothing to alter the relative disposition of mountain and plain in this part of Persia, or to change the general character of its ancient highway. All this part of Persia was under the dominion of the Assyrian king when the tribes of Israel left Syria for Armenia. He had but recently traversed the road to India, and he knew the richness of Baktria (of Afghan Turkistan and Badakshan) and could estimate what a colony might become in these eastern fields.