The throne of Armenia, a country at the confluence of Roman and Parthian influences, was informally consulted and established between the two then powers over the years. When in 110 CE king Osroes I of the Parthians appointed his nephew Axidares, son of former king Pacorus II, to the throne of Armenia, there was a breach of an unwritten rule, and Rome was not asked to accept the new candidacy.
This turn of events was in the hand of Trajan, who after the victorious wars against the Dacias, planned to make conquests in the east at the expense of the divided Parthian kingdom. Growing tensions on the Rome-Parthia line and internal struggles forced Osroes to exchange Axidares in 113 CE for another son of Pacorus – Parthamasiris – which he wanted to ease the situation. However, Trajan’s decision to start the war had already been made, and the actions of the Parthian king were considered casus belli.
The conquest of Armenia by the Roman army was extremely efficient and without large losses, as the cities were either conquered by deception or they surrendered themselves. Cassius Dio reports that Parthamasiris was aware that he would not be able to stop Trajan’s aggression and it would be better to negotiate terms of cooperation. The king of Armenia asked for a private audience with the emperor, who, however, did not treat him as a real conversation partner and ruled out any rights to the throne. Trajan made it clear that Armenia would become part of the Empire and would merge with Cappadocia to form a new province under his trusted man Lucius Catilius Severus.
Parthamasiris was sentenced to exile, and many of the local nobles accompanying him became hostages of the Romans. As it turned out, Trajan’s plan was to get rid of Parthamasiris, who had been assigned a cavalry squad to be his “escort”. The former Armenian king, granted by the Parthians, officially died trying to escape; in practice, he was taken outside the camp and murdered. Trajan then informed the Parthian king of his nephew’s “unfortunate” death.
