Through Arachosia and Drangiane, in the valley of the Etymander (Helmand), he marched to Carmania and Persis (Polyb.
In other districts, also, rebellions occurred; and in the east, Euthydemus and his successors (Demetrius, Eucratidas, &c.) began the conquest of the Indus region and the Iranian borderland (Arachosia, Aria).
There were indeed vassal states on every hand, but the actual possessions of the kingsthe provinces governed by their satrapsconsisted of a rather narrow strip of land, stretching from the Euphrates and north Babylonia through southern Media and Parthia as far as Arachosia (north-west Afghanistan), and following the course of the great trade-route which from time immemorial had carried the traffic between the west of Asia and India.
(12) Parthyene with Parthaunisa, where the sepulchres of the kings were laid; (13) Apavarcticene (flow Abiward, with the capital Kelat); (14) Margiane (Merv); (i 5) Aria (Herat); (16) Anauon, the southern portion of Aria; (17) Zarangiane, the country of the Drangians, on the lake of Hamun; (18) Arachosia, on the Etymander (Helmand), called by the Parthians White India, extending as far as Alexandropolis (Kandahar), the frontier city of the Parthian Empire.
The east of IranBactria with Sogdiana, Eastern Arachosia and Gedrosiawas never subject to the Arsacids.