Then it was that while the forces of the East were divided, and hesitated which side they should take, the opportunity of occupying Armenia was presented to Mithridates, who had the vigorous soldiers of Rome to storm the fortified heights, while his Iberian cavalry scoured the plain. The Armenians made no resistance after their governor, Demonax, had ventured on a battle and had been routed. Cotys, king of Lesser Armenia, to whom some of the nobles inclined, caused some delay, but he was stopped by a despatch from Claudius, and then everything passed into the hands of Mithridates, who showed more cruelty than was wise in a new ruler. The Parthian princes however, just when they were beginning battle, came to a sudden agreement, on discovering a plot among their people, which Gotarzes revealed to his brother. At first they approached each other with hesitation; then, joining right hands, they promised before the altars of their gods to punish the treachery of their enemies and to yield one to the other. Vardanes seemed more capable of retaining rule. Gotarzes, to avoid all rivalry, retired into the depths of Hyrcania. When Vardanes returned, Seleucia capitulated to him, seven years after its revolt, little to the credit of the Parthians, whom a single city had so long defied.
Complete Works of Tacitus. Tacitus. Alfred John Church. William Jackson Brodribb. Sara Bryant. edited for Perseus. New York. : Random House, Inc. Random House, Inc. reprinted 1942.
