It was after the third century, when the tribal groups - Avars, Bulgars, Huns, Slavs, and Magyars got some land in exchange for peace by the Romans. But they turned hostile towards them later on. It was the barbarians that truly changed the course of history and almost destroyed the Western Roman Empire. The Goths deposed the last western Roman Emperor (Romulus Augustus) and it was this episode that witnessed the beginning of the Middle Ages.