Under Nero, the Romans fought a campaign (55–63) against the Parthian Empire, which had invaded the kingdom of Armenia, allied to the Romans. After gaining (60) and losing (62) Armenia, the Romans under Gnaeus Domitius Corbulo, legate of Syria entered (63) into an agreement of Vologases I of Parthia, which confirmed Tiridates I as king of Armenia, thus founding the Arshakuni dynasty.