 Armenia had been divided during the reign of Shapur III according to the terms of a peace treaty.But this arrangement barely survived the reign of Bahram IV.In 389, Khosrov IV, the vassal king of Armenia under Sasanian suzerainty grew wary of his subordination to Iran and entered into a treaty with the Roman emperor Theodosius I, who made him the king of a united Armenia in return for his allegiance.