one of the rival claimants to the throne of the Parthian king Pacorus II.

He first presented himself as the ruler of Parthia in 105/106 and seems to have been able to persist in his claim throughout the reign of Osroes (c. 109/110–c. 128/129). On the death of Osroes, Vologeses was able to overcome another rival, Mithradates IV, and to secure the greater part of the Parthian realm, which he ruled until his death.