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.
Henry IV, Holy Roman Emperor
The Romans soon fell away from their allegiance to the pope. Recalled to the city, Henry entered Rome in March 1084, after which Gregory was declared deposed and Antipope Clement III was elected by the Romans. On 31 March 1084 Henry was crowned emperor by Clement and received the patrician authority. His next step was to attack the fortresses still in the hands of Gregory. The pope was saved by the advance of Robert Guiscard, duke of Apulia, who left the siege of Durazzo and marched towards Rome: Henry left the city and Gregory was freed. Gregory soon died at Salerno, in 1085, but not before a last letter in which he exhorted the whole of Christianity to a crusade against the Emperor.