Roman Empire vs. Holy Roman Empire

Roman Empire

noun

the lands and peoples subject to the authority of ancient Rome.
the form of government established in ancient Rome in 27 b.c., comprising the Principate or Early Empire (27 b.c.–a.d. 284) and the Autocracy or Later Empire (a.d. 284–476).
a later empire, as that of Charlemagne or the Byzantine Empire, regarded as a restoration or continuation of the ancient Roman Empire or one of its branches.

Holy Roman Empire

a Germanic empire located chiefly in central Europe that began with the coronation of Charlemagne as Roman emperor in a.d. 800 (or, according to some historians, with the coronation of Otto the Great, king of Germany, in a.d. 962) and ended with the renunciation of the Roman imperial title by Francis II in 1806, and was regarded theoretically as the continuation of the Western Empire and as the temporal form of a universal dominion whose spiritual head was the pope.