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.
Sack of Rome (410)
The sack was a culmination of many terminal problems facing the Western Roman Empire. Domestic rebellions and usurpations weakened the Empire in the face of external invasions. These factors would permanently harm the stability of the Roman Empire in the west. The Roman army meanwhile became increasingly barbarian and disloyal to the Empire. A more severe sack of Rome by the Vandals followed in 455, and the Western Roman Empire finally collapsed in 476 when the Germanic Odovacer removed the last Western Roman Emperor, Romulus Augustulus, and declared himself King of Italy.