The Sassanid Empire is the new Persian Empire under the rule of a family of powerful kings. Eventually after Marcus Aurelius' rule of Rome the later Emperors lost territory and the Sassanid Empire proclaimed the eastern section of the Roman Empire their own. The Romans tried to reclaim those lands but the empire was collapsing by constant attacks in the western section of the Empire. The Sassanid took advantage of this and eventually helped the creation of the Byzantine Empire. The Visigoths might be the only other force that the Roman Empire grew to fear. Marcus Aurelius warned the Empire to avoid war against these people. Eventually the Visigoths started invading the Roman territories and successfully obtained cities and areas. So the Empire was being attacked by both sides, one by the Visigoths and the other by the Sassanid forces. Eventually the Visigoths took control of western Rome and dissolved the Empire with dictatorship after dictatorship. The reason why the Romans feared the Visigoths is because of the savage nature of fighting and ruthless war tactics.