Early modern period
In the early modern period, the Holy Roman Empire was a union of territories in Central Europe under a Holy Roman Emperor the first of which was Otto I. The last was Francis II, who abdicated and dissolved the Empire in 1806 during the Napoleonic Wars. Despite its name, for much of its history the Empire did not include Rome within its borders.
Roman emperor
Constantine XI Palaiologos was the last reigning Roman emperor. A member of the Palaiologos dynasty, he ruled the remnant of the Eastern Roman Empire from 1449 until his death in 1453 defending its capital Constantinople.