Charlemagne was King of the Franks from 768 until his death. He expanded the different Frankish kingdoms until transforming them into an Empire that incorporated a large part of Western and Central Europe. He conquered Italy and was crowned Imperator Augustus by Pope Leo III on December 25, 800 in Rome.
In this way he succeeded the Byzantine Empire as protector of Christianity. Before the initial indignation of Constantinople, in 812 an agreement was signed between the two leaders, and again there were two emperors in Europe, one in the East and one in the West.
His reign has been commonly associated with the Carolingian Renaissance, a revival of Latin culture and art through the Carolingian Empire and led by the Catholic Church. Through his foreign conquests and internal reforms, Charlemagne laid the foundations for what would become Western Europe in the Middle Ages. In the French, German and Holy Roman monarchies, he is referred to as Charles I.