Strabo Geography 11.14.2

[2] For the Euphrates, having its beginnings on the northern side of the Taurus, flows at first towards the west through Armenia, and then bends towards the south and cuts through the Taurus between Armenia, Cappadocia, and Commagene, and then, after falling outside the Taurus and reaching the borders of Syria, it bends towards the winter-sunrise ¹ as far as Babylon, and with the Tigris forms Mesopotamia; and both rivers end in the Persian Gulf. Such, then, is our circuit of Armenia, almost all parts being mountainous and rugged, except the few which verge towards Media. But since the above-mentioned Taurus ² takes a new beginning on the far side of the Euphrates opposite Commagene and Melitene, countries formed by that river, Mt. Masius is the mountain which ties above the Mygdonians of Mesopotamia on the south, in whose country is Nisibis, whereas Sophene is situated in the northern parts, between Masius and Antitaurus. The Antitaurus takes its beginning at the Euphrates and the Taurus and ends towards the eastern parts of Armenia, thus on one side enclosing the middle of Sophene, ³ of the Euphrates, before that river bends towards the south. The royal city of Sophene is Carcathiocerta. Above Mt. Masius, far towards the east opposite Gordyene, lies Mt. Niphates; and then comes Mt. Abus, whence flow both the Euphrates and the Araxes, the former towards the west and the latter towards the east; and then Mt. Nibarus, which stretches as far as Media.