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.
Roman triumph
For triumphs of the Roman regal era, the surviving Imperial "Fasti Triumphales" are incomplete. After three entries for the city's legendary founder Romulus, eleven lines of the list are missing. Next in sequence are Ancus Marcius, Tarquinius Priscus, Servius Tullius, and finally Tarquin "the proud", the last king. The "Fasti" were compiled some five centuries after the regal era, and probably represent an approved, official version of several different historical traditions. Likewise, the earliest surviving written histories of the regal era, written some centuries after it, attempt to reconcile various traditions, or else debate their merits. Dionysus, for example, gives Romulus three triumphs, the same number given in the "Fasti". Livy gives him none, and credits him instead with the first spolia opima, in which the arms and armour were stripped off a defeated foe, then dedicated to Jupiter. Plutarch gives him one, complete with chariot. Tarquin has two triumphs in the "Fasti" but none in Dionysius. No ancient source gives a triumph to Romulus' successor, the peaceful king Numa.