<P> The Tetrarchy ended, but the idea of dividing the Roman Empire between two emperors had been validated . Very strong emperors would reunite it under their single rule, but with their death the Roman Empire would be divided again and again between the East and the West . </P> <P> Constantius was born in 317 at Sirmium, Pannonia . He was the third son of Constantine the Great, and second by his second wife Fausta, the daughter of Maximian . Constantius was made Caesar by his father on 13 November 324 . The Roman Empire was under the rule of a single Emperor, but, with the death of Constantine in 337, civil war erupted among his three sons, dividing the Empire into three parts . The West was unified in 340 under Constans, who was assassinated in 350 under the order of the usurper Magnentius; after Magnentius lost the Battle of Mursa Major and committed suicide, a complete reunification of the whole Empire occurred in 353, with Constantius II . </P> <P> Constantius II focused most of his power in the East and is regarded as the first emperor of the Byzantine Empire . Under his rule, the city of Byzantium - only recently re-founded as Constantinople - was fully developed as a capital . In 361, Constantius II became ill and died, and Constantius Chlorus' grandson Julian, who had served as Constantius II's Caesar, assumed power . Julian was killed in 363 in the Battle of Samarra against the Persian Empire and was succeeded by Jovian, who ruled only until 364 . </P> <P> Following the death of Jovian, Valentinian I emerged as Emperor in 364 . He immediately divided the Empire once again, giving the eastern half to his brother Valens . Stability was not achieved for long in either half, as the conflicts with outside forces (tribes) intensified . In 376, the Visigoths, fleeing before the Ostrogoths, who in turn were fleeing before the Huns, were allowed to cross the river Danube and settle into the Balkans by the Eastern government . Mistreatment caused a full - scale rebellion, and in 378 they inflicted a crippling defeat on the Eastern Roman field army in the Battle of Adrianople, in which Valens also died . The campaigns to subdue them were only partly successful, and they officially became semi-independent foederati under their own leaders . </P>

Name three characteristics of the roman empire before the western half collapsed