The capital of the Holy Roman Empire was primarily the city of Aachen, especially during the reign of Charlemagne in the early medieval period. However, it is important to note that the empire was vast and included many territories, which meant that the seat of power could shift based on the emperor’s preferences. Later on, cities like Frankfurt and Regensburg also played significant roles as locations for imperial diets and ceremonies.
Aachen was significant because it was the site of Charlemagne’s palatial complex and served as the emperor’s favorite residence. It was also here that he was crowned as Emperor of the Romans in 800 AD, which solidified its importance as a political and spiritual center of the empire.
Over time, the decentralized nature of the Holy Roman Empire meant that no single city acted as a formal capital in the way modern states do. Instead, various cities, particularly the aforementioned Aachen, served as important centers of power and governance throughout the empire’s history.