History of Europe
In 395 Theodosius I, who had made Christianity the official religion of the Roman Empire, would be the last emperor to preside over a united Roman Empire. The empire was split into two halves: the Western Roman Empire centred in Ravenna, and the Eastern Roman Empire (later to be referred to as the Byzantine Empire) centred in Constantinople. The Roman Empire was repeatedly attacked by Hunnic, Germanic, Slavic and other “barbarian” tribes (see: Migration Period), and in 476 finally the Western part fell to the Heruli chieftain Odoacer.
History of Rome
In 480, the last Western Roman emperor, Julius Nepos, was murdered and a Roman general of barbarian origin, Odoacer, declared allegiance to Eastern Roman emperor Zeno. Despite owing nominal allegiance to Constantinople, Odoacer and later the Ostrogoths continued, like the last emperors, to rule Italy as a virtually independent realm from Ravenna. Meanwhile, the Senate, even though long since stripped of wider powers, continued to administer Rome itself, with the Pope usually coming from a senatorial family. This situation continued until Theodahad murdered Amalasuntha, a pro-imperial Gothic queen, and usurped the power in 535. The Eastern Roman emperor, Justinian I (reigned 527–565), used this as a pretext to send forces to Italy under his famed general Belisarius, recapturing the city next year. The Byzantines successfully defended the city in a year-long siege, and eventually took Ravenna.