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.
List of Roman emperors
In the late 3rd century, after the Crisis of the Third Century, Diocletian formalised and embellished the recent manner of imperial rule, establishing the so-called Dominate period of the Roman Empire. This was characterised by the explicit increase of authority in the person of the Emperor, and the use of the style ("Our Lord"). The rise of powerful Barbarian tribes along the borders of the empire and the challenge they posed to defense of far-flung borders and unstable imperial succession led Diocletian to divide the administration geographically of the Empire in 286 with a co-Augustus. In 330, Constantine the Great established a second capital in Byzantium, which he renamed Constantinople. For most of the period from 286 to 480, there was more than one recognised senior emperor, with the division usually based in geographic terms. This division was consistently in place after the death of Theodosius I in 395, which historians have dated as the division between the Western Roman Empire and the Eastern Roman Empire. However, formally the Empire remained a single polity, with separate co-emperors in the separate courts. The fall of the Western Roman Empire, and so the end of a separate list of emperors below, is dated either from the date of 476 when Romulus Augustulus was deposed by Odoacer who became King of Italy, or the date of 480, on the death of Julius Nepos, when Eastern Emperor Zeno ended recognition of a separate Western court. In the period that followed, the Empire is usually treated by historians as the Byzantine Empire governed by the Byzantine Emperors, although this designation is not used universally, and continues to be a subject of specialist debate today.