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.
The Last Legion
The Emperor Tiberius is referred to as "the last of Julius Caesar's line". Inconsistently, Romulus Augustulus is also depicted as the last of Julius Caesar's family line and Tiberius as one of his ancestors. Tiberius was actually the second of the five Julio-Claudian emperors, succeeding to the role of emperor as the adopted son of Augustus, who had himself been adopted by Julius Caesar. Augustus had named several of his own relatives as heirs, but as they all died, he named a son of his second wife, Livia, by her first marriage. Thus, Tiberius was not the last of any line established by Julius Caesar (Augustus' maternal great-uncle by blood) as he had no blood relation to Caesar at all. His successors, Caligula and Claudius were blood relatives of Julius Caesar through a maternal blood line dating back to Augustus's older sister, Octavia. Nero, a direct descendant of Augustus, ruled roughly twenty years after the death of Tiberius and was the final emperor of the Julio-Claudian Dynasty, thus making him the last ruler descended from Julius Caesar's family – the Julii.