Tiberius was emperor of the Roman Empire from 14-37. He was not actively involved in the politics of the empire. In the early years of his reign, it was Germanicus who avenged the Roman honour in Germania in 14-16, without conquering the area. Cappadocia and Commagene were annexed in 17 after the death of their kings Archelaus of Cappadocia and Antiochus III of Commagene. Germanicus avoided war with king Artabanus II of the Parthian Empire by replacing Vonones I with Artaxias III as Roman vassal king of Armenia in 18. Between 15 and 25, the Romans fought a war against Tacfarinas of the Berber Musulamii tribe in Africa.
In 28, the Frisians revolted. The Romans tried to subdue the revolt, but with no success.
In the 30s, the Roman Empire suffered from Germanic and Dacian raids.
Artabanus II of the Parthian Empire invaded Armenia after the death of Artaxias III in 34, and turned it into a Parthian vassal by puting his son on the throne. Governor Lucius Vitellius of Syria retaliated by letting Armenia be reconquered for the Romans by king Pharasmanes I of Caucasian Iberia. The brother of Pharasmanes, Mithridates became king of Armenia as Roman vassal in 35. Artabanus II and Vitellius made peace between the Romans and the Parthians in 37.