Of this monarch, whose achievements (according to Justin) procured him the epithet of "the Great," the accounts which have come down to us are extremely scanty and unsatisfactory.

Justin, who is our principal informant on the subject of the early Parthian history, has unfortunately confounded him with the third monarch of the name, who ascended the throne more than sixty years later, and has left us only the slightest and most meagre outline of his actions.

The other classical writers, only to a very small extent, supplement Justin's narrative; and the result is that of a reign which was one of the most important in the early Parthian series, the historical inquirer at the present day can form but a most incomplete conception.
It appears, however, from the account of Justin, and from such other notices as have reached us of the condition of things at this time in the regions lying east of the Caspian, that Mithridates was entirely successful where his father and his cousin had signally failed.

He gained a number of victories over the Scythic hordes; and effectually checked their direct progress towards the south, throwing them thereby upon the east and the south-east.

Danger to Parthia from the Scyths seems after his reign to have passed away.