 Complete the following phrase:  Trajans successor Hadrian r. 117138 AD reaffirmed the Roman-Parthian border at the Euphrates, choosing not to invade Mesopotamia due to Romes now limited military resources. Parthamaspates fled after the Parthians revolted against him, yet the Romans made him king of Osroene. Osroes I died during his conflict with Vologases III, the latter succeeded by Vologases IV of Parthia r. c. 147191 AD who ushered in a period of peace and stability. However, the 