Charlemagne was King of the Franks from 768, King of the Lombards from 774, and Emperor of what is now known as the Carolingian Empire from 800, holding all these titles until his death in 814. Charlemagne succeeded in uniting the majority of Western Central Europe, and was the first recognized emperor to rule in the west after the fall of the Western Roman Empire approximately three centuries earlier. Charlemagne's rule saw a program of political and social changes that had a lasting impact on Europe in the Middle Ages.

The Carolingian Empire (800–887) was a Frankish-dominated empire in western and central Europe during the Early Middle Ages. It was ruled by the Carolingian dynasty, which had ruled as kings of the Franks since 751 and as kings of the Lombards in Italy from 774. In 800, the Frankish king Charlemagne was crowned emperor in Rome by Pope Leo III in an effort to transfer the Roman Empire from the Byzantine Empire to Western Europe. The Carolingian Empire is sometimes considered the first phase in the history of the Holy Roman Empire.