Final answer:
Charlemagne's title of Holy Roman Emperor symbolized his power, the Church's endorsement, and his ambitions to unite and rule Europe. It marked a significant moment in European history, melding Roman traditions with Germanic kingship and Christianity, and triggering the Carolingian Renaissance—an attempt to revive learning and culture in medieval Europe.
Step-by-step explanation:
The title of Holy Roman Emperor bestowed upon Charlemagne in 800 by Pope Leo III signified not just the temporal authority Charlemagne wielded over the vast territories of Western Europe, but also the spiritual endorsement of his rule by the Catholic Church. By crowning Charlemagne, Leo III was attempting to revive the glory of the Roman Empire in the West and asserting the Church's influence on secular matters. This coronation effectively melded a Germanic king's military conquest with the Roman imperial tradition and the Christian religion. The title also suggested Charlemagne's role as the protector of Christianity and his divine right to rule, as well as indicating his ambition to dominate Europe both militarily and politically.
As Emperor, Charlemagne integrated various Germanic groups into a single entity and attempted to revive Roman-style governance and culture in what became known as the Carolingian Renaissance. His rule established precedents for the transference of kingship across different clans and kingdoms through conquest and political maneuvering, setting the stage for how medieval European empires would be ruled. Charlemagne's legacy lasted long after his reign with the Holy Roman Empire's existence, which survived until its dissolution by Napoleon in 1806.