Trajan's Mesopotamian Campaign

Timeline

1. 115Armenia · ArmeniaTrajan declared war on the pretext that Parthia had installed a puppet king in Armenia, marched east defeating Parthian forces, made Armenia a Roman province, and continued advancing southward.
2. 116Ctesiphon and Seleucia · MesopotamiaRoman legions marched south to occupy Mesopotamia, capturing Seleucia and the Parthian capital Ctesiphon; Trajan reached the Persian Gulf and claimed to have arrived at the end of the world. The empire briefly established the provinces of Assyria and Mesopotamia.
3. 117Cilicia · CiliciaRebellions broke out in the newly annexed eastern regions, and Trajan fell ill and died while returning with his army. His successor Hadrian abandoned most newly conquered territories including Mesopotamia, restoring the balance of power with Parthia.