Seleucus therefore allowed the Mardians to be reduced, conceiving, probably, that their transfer to the dominion of the Arsacidse neither increased the Parthian power nor diminished his own.
But the nation which submits to be robbed of a province, however unproductive and valueless, must look to having the process repeated at intervals, until it bestirs itself and offers resistance.

There is reason to believe that Phraates had no sooner conquered the Mardians than he cast his eyes on an adjacent district, and resolved to add it to his territories.

This was the tract lying immediately to the West of the Caspian Gates, which was always reckoned to Media, forming, however, a distinct district, know as Media Rhagiana.

It was a region of much natural fertility, being watered by numerous streams from the Elburz range, and possessing a soil of remarkable productiveness.

Its breadth was not great, since it consisted of a mere strip between the mountains and the Salt Desert which occupies the whole centre of the Iranic tableland; but it extended in length at least a hundred and fifty miles, from the Caspian Gates to the vicinity of Kasvin.