Elated by this success, he is said to have pressed eastward, to have invaded India, and overrun the country as far as the river Hydaspes, but, if it be true that his arms penetrated so far, it is, at any rate, certain that he did not here effect any conquest.

Greek monarchs of the Bactrian series continued masters of Oabul and Western India till about B.C.

126; no Parthian coins are found in this region; nor do the best authorities claim for Mithridates any dominion beyond the mountains which enclose on the west the valley of the Indus.
By his war with Heliocles the empire of Mithridates reached its greatest extension.

It comprised now, besides Parthia Proper, Bactria, Aria, Drangiana, Arachosia, Margiana, Hyrcania, the country of the Mardi, Media Magna, Susiana, Persia and Babylonia.

Very probably its limits were still wider.