 Meanwhile, the Roman emperor Carus, hearing of the civil war occurring in the Sasanian Empire, chose to take advantage of the situation by making a campaign into the empire in 283.He invaded Mesopotamia while Bahram II was in the east, and even besieged the Sasanian capital of Ctesiphon without facing much fighting.The Sasanians, due to facing severe internal problems, were unable to mount an effective coordinated defense at the time; Carus and his army may have captured Ctesiphon.