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.
Antoninus Pius
Antoninus was the last Roman Emperor recognised by the Indian Kingdoms. Raoul McLaughlin quotes Aurelius Victor as saying "The Indians, the Bactrians and the Hyrcanians all sent ambassadors to Antoninus. They had all heard about the spirit of justice held by this great emperor, justice that was heightened by his handsome and grave countenance, and his slim and vigorous figure." Due to the outbreak of the Antonine epidemic and wars against northern Germanic tribes, the reign of Marcus Aurelius was forced to alter the focus of foreign policies, and matters relating to the Far East were increasingly abandoned in favour of those directly concerning the Empire's survival.