Which city was Charlemagne crowened in?

Charlemagne was crowned in Rome on December 25, 800 AD. The coronation took place in St. Peter's Basilica, where Pope Leo III placed the crown on his head, marking the establishment of the Carolingian Empire and symbolizing the fusion of Roman, Christian, and Germanic elements in medieval Europe. This event is often seen as a pivotal moment in European history, reinforcing the idea of a united Christendom under a single ruler.