Mithridates, their protege, had displeased them, and had been summoned to Rome by Caligula, who kept him there a prisoner until his death.

Armenia, left without a king, had asserted her independence; and when, after an absence of several years, Mithridates was authorized by Claudius to return to his kingdom, the natives resisted him in arms, and were only brought under his rule by the combined help of the Romans and the Iberians.

Forced upon a reluctant people by foreign arms, Mithridates felt himself insecure, and this feeling made him rule his subjects with imprudent severity.

Under these circumstances it seemed to Vardanes that it would not be very difficult to recover Armenia, and thus gain a signal triumph over the Romans.
But to engage in so great a matter with a good prospect of success it was necessary that the war should be approved, not only by himself, but by his principal feudatories.

The most important of these was now Izates, king of Adiabene and Gordyene who in the last reign had restored Artabanus to his lost throne.