But, indeed, even before that he was a formidable enemy owing to the importance of his province. For the whole of the royal horses out at grass are entrusted to the Medes; and they have an incalculable quantity of corn and cattle. Of the natural strength and extent of the district it would be impossible to speak highly enough. For Media lies nearly in the centre of Asia and in its size, and in the height of its steppes compares favourably with every other district of Asia. And again it overlooks some of the most warlike and powerful tribes. On the east lie the plains of the desert which intervenes between Persia and Parthia; and, moreover, it borders on and commands the “Caspian Gates,” and touches the mountains of the Tapyri, which are not far from the Hyrcanian Sea. On the south it slopes down to Mesopotamia and the territory of Apollonia. It is protected from Persia by the barrier of Mount Zagrus, which has an ascent of a hundred stades, and containing in its range many separate peaks and defiles is subdivided by deep valleys, and at certain points by cañons, inhabited by Cosseans, Corbrenians, Carchi, and several other barbarous tribes who have the reputation of being excellent warriors. Again on the west it is coterminous with the tribe called Satrapeii, who are not far from the tribes which extend as far as the Euxine. Its northern frontier is fringed by Elymaeans, Aniaracae, Cadusii, and Matiani, and overlooks that part of the Pontus which adjoins the Maeotis. Media itself is subdivided by several mountain chains running from east to west, between which are plains thickly studded with cities and villages.