Roman emperor
The Western Roman Empire collapsed in the late 5th century. Romulus Augustulus is often considered to be the last emperor of the West after his forced abdication in 476, although Julius Nepos maintained a claim recognized by the Eastern Empire to the title until his death in 480. Following Nepos' death, the Eastern Emperor Zeno abolished the division of the position and proclaimed himself as the sole Emperor of a reunited Roman Empire. The Eastern imperial lineage continued to rule from Constantinople ("New Rome"); they continued to style themselves as Emperor of the Romans (later βασιλεύς Ῥωμαίων in Greek), but are often referred to in modern scholarship as Byzantine emperors. Constantine XI Palaiologos was the last Roman emperor in Constantinople, dying in the Fall of Constantinople to the Ottomans in 1453.
Campaign history of the Roman military
The Empire became gradually less Romanised and increasingly Germanic in nature: although the Empire buckled under Visigothic assault, the overthrow of the last Emperor Romulus Augustus was carried out by federated Germanic troops from within the Roman army rather than by foreign troops. In this sense had Odoacer not renounced the title of Emperor and named himself "King of Italy" instead, the Empire might have continued in name. Its identity, however, was no longer Roman – it was increasingly populated and governed by Germanic peoples long before 476 AD. The Roman people were by the 5th century "bereft of their military ethos" and the Roman army itself a mere supplement to federated troops of Goths, Huns, Franks and others fighting on their behalf.