Visigoths
The Visigoths were a confederacy of Germanic tribes, who migrated from the Baltic area to the Danube River, pressed by the advancing Huns. They were offered entrance into Rome territory on peaceful terms by the Emperor Valens. However, the Visigoths and Romans had a falling out and the Visigoths rose up against the Romans and crushed their main army at the Battle of Adrianople. As the Roman Empire became more shaky, they found it more difficult to stop the Visigoths and other barbarian tribes. This culminated in the Visigoth sacking of Rome in 410 A.D., under the rule of Alaric I. Saint Augustine chronicled this horrific defeat, and the shockwave it sent throughout the world, intellectually and physically, in his major work, City of God."
Following the collapse of the Roman Empire, the Visigoths gained control over Rome when they deposed Romulus Augustulus, the last emperor, in 476 A.D. However, they were later defeated by the Ostrogoths under the command of Theoderic, on orders from the Byzantine ruler Zeno.