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.
Frederick III, Holy Roman Emperor
In 1452, at the age of 37, Frederick III travelled to Italy to receive his bride and to be crowned Holy Roman Emperor. His fiancée, the 18-year-old "infanta" Eleanor, daughter of King Edward of Portugal, landed at Livorno (Leghorn) after a 104-day trip. Her dowry would help Frederick alleviate his debts and cement his power. The couple met at Siena on 24 February and proceeded together to Rome. As per tradition, they spent a night outside the walls of Rome before entering the city on 9 March, where Frederick and Pope Nicholas V exchanged friendly greetings. Because the emperor had been unable to retrieve the Iron Crown of Lombardy from the cathedral of Monza where it was kept, nor be crowned King of Italy by the archbishop of Milan (on account of Frederick's dispute with Francesco Sforza, lord of Milan), he convinced the pope to crown him as such with the German crown, which had been brought for the purpose. This coronation took place on the morning of 16 March, in spite of the protests of the Milanese ambassadors, and in the afternoon Frederick and Eleanor were married by the pope. Finally, on 19 March, Frederick and Eleanor were anointed in St Peter's Basilica by the Vice-Chancellor of the Holy Roman Church, Cardinal Francesco Condulmer, and Frederick was then crowned with the Imperial Crown by the pope. Frederick was the last Emperor to be crowned in Rome; his great-grandson Charles V was the last emperor to be crowned, but this was done in Bologna.