Ecbatana,[240] the capital of Media, was built[241] by king Seleucus, at a distance from Great Seleucia of seven hundred and fifty miles, and twenty miles from the Caspian Gates. The remaining towns of the Medians are Phazaca, Aganzaga, and Apamea,[242] surnamed Rhagiane. The reason of these passes receiving the name of “Gates,” is the same that has been stated above.[243] The chain of mountains is suddenly broken by a passage of such extreme narrowness that, for a distance of eight miles, a single chariot can barely find room to move along: the whole of this pass has been formed by artificial means. Both on the right hand and the left are overhanging rocks, which look as though they had been exposed to the action of fire; and there is a tract of country, quite destitute of water, twenty-eight miles in extent. This narrow pass, too, is rendered still more difficult by a liquid salt which oozes from the rocks, and uniting in a single stream, makes its way along the pass. Besides this, it is frequented by such multitudes of serpents, that the passage is quite impracticable except in winter. (15.) Joining up to Adiabene are the people formerly known as the ‘Carduchi,’ now the Cordueni,[244] in front of whom the river Tigris flows: and next to them are the Pratitæ, entitled the _Par Odon_,[245] who hold possession of the Caspian Gates.[246] On the other side[247] of these gates we come to the deserts[248] of Parthia and the mountain chain of Cithenus; and after that, the most pleasant locality of all Parthia, Choara[249] by name. Here were two cities of the Parthians, built in former times for their protection against the people of Media, Calliope,[250] and Issatis, the last of which stood formerly[251] on a rock. Hecatompylos,[252] the capital of Parthia, is distant from the Caspian Gates one hundred and thirty-three miles. In such an effectual manner is the kingdom of Parthia shut out by these passes. After leaving these gates we find the nation of the Caspii, extending as far as the shores of the Caspian, a race which has given its name to these gates as well as to the sea: on the left there is a mountainous district. Turning back[253] from this nation to the river Cyrus, the distance is said to be two hundred and twenty miles; but if we go from that river as far down as the Caspian Gates, the distance is seven hundred[254] miles. In the itineraries of Alexander the Great these gates were made the central or turning point in his expeditions; the distance from the Caspian Gates to the frontier of India being there set down as fifteen thousand six hundred and eighty[255] stadia, to the city of Bactra,[256] commonly called Zariaspa, three thousand seven hundred, and thence to the river Jaxartes[257] five thousand stadia. CHAP. 18. (16.)—NATIONS SITUATE AROUND THE HYRCANIAN SEA.