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.
The Last Legion
Orestes, who was partly of Germanic blood, was historically the "magister militum" – the senior officer of the Roman army second to the emperor. He had indeed promised his Germanic foederati a third of Italy to settle in but not to Odoacer personally. Orestes was himself a usurper, having promised the land to foederati to buy their quiescence in his rebellion against the legitimate emperor Julius Nepos. Although Orestes proclaimed his son, Romulus Augustus (derisively called "Augustulus", meaning "little Augustus") Emperor, the proclamation was not recognised as legitimate beyond the parts of the Italian Peninsula controlled by Orestes' troops. The common identification of Augustus as the "last Western Emperor" dates only from the publication of British historian Edward Gibbon's History of the Decline and Fall of the Roman Empire in the late 18th Century.