Osroes I

Osroes I was a Parthian Arsacid king whose unilateral installation of Axidares on the Armenian throne without Roman approval gave Emperor Trajan the pretext for Rome's most ambitious eastern campaign. Trajan annexed Armenia in 114 CE, then Mesopotamia and Assyria in 115–116 CE, reaching the Persian Gulf and briefly capturing the Parthian capital Ctesiphon. A widespread revolt in the conquered territories and Trajan's death in 117 CE forced his successor Hadrian to abandon most of the gains, restoring the traditional Euphrates boundary. Osroes died around 129 CE.

MyHistorian
A causal knowledge graph of history