Parthamaspates, the son of Osroes I, spent much of his life in Romanexile. He accompanied the Roman Emperor Trajan on his campaign to conquer Persia. Emperor Trajan originally planned to annex Persia as part of the Roman Empire, but decided to place Parthamaspates on the Persian throne as a Roman client-king, which he did on 116. Following Roman withdrawal from the area, Chosroes easily defeated Parthamaspates to reclaim the Persian throne.
After his defeat in Persia, Parthamaspates again fled to the Romans who then, as a consolation, granted him rule of Osrhoene, a small Roman client-state.
A.D. Parthamaspates gained the Parthian throne by acting as a Roman collaborator.
After the Roman withdrawal, however, Parthamaspates was easily defeated by Osroes and fled to the Romans who granted him the small Roman client state of Osrhoene in consolation.
Although signed with the Ecbatana monogram, Parthamaspates' drachms may have been struck at Ctesiphon by the Romans after Trajan proclaimed him king.