The history of the Middle East during the century following Augustus’ establishment of the Principate in Rome was dominated by the focus of both Rome and Parthia on control of the buffer states along the frontier separating the two empires. Of particular strategic importance in this regard was Armenia, which provided an alternate northern route across or around the Euphrates between Parthia and Syria or Asia Minor. Accordingly, both empires sought to include Armenia within their spheres of interest.
Armenia, with Parthian support, had been under the unchallenged rule of Artaxias II (34–20) since the withdrawal of the Roman legions under Antonius from the country. Adecade later, however, a group of Armenian nobles sought to replace Artaxias on the throne with his younger brother Tigranes, who had been held prisoner by the Romans since 34 when he was sent to Egypt by Antonius along with his father Artavasdes. This development provided Augustus with the opportunity to replace Parthian influence in Armenia with Roman, and he dispatched his stepson Tiberius to place Tigranes on the Armenian throne in response to the request to intervene in the crisis. Although Artaxias was killed before the Roman force arrived, Tigranes II received his crown from Tiberius, who also placed a Roman client-prince, Ariobarzanes, on the throne of Media Atropatene (Azerbaijan). For the next decade and a half, Roman influence was dominant in the region of the upper Euphrates and the gateways into Parthia.
The situation along the Roman-Parthian frontier became destabilized once again with the death of Tigranes about 6 B.C.E., as both powers sought to intervene in their interests in the question of the Armenian succession. Notwithstanding the attempt of Augustus to influence matters by dispatching his adopted son Gaius Caesar with a Roman force to Armenia in