Charlemagne, first emperor of the Holy Roman Empire Painting by Dürer

Charlemagne became the sole ruler of the Franks in 771 and spent the first portion of his reign extending his rule, conquering the Avars, Pannonia, Britanny, northern Spain, and Bavaria. In 800 the pope crowned Charlemagne Holy Roman Emperor in the West. Throughout his reign Charlemagne was an advocate of the papacy, mentor of reformers, friend of monasticism, and a patron of learning. His palace school at Aachen became a center for training civil administrators and ecclesiastical reformers. In view of this modern scholars often speak of a Carolingian renaissance. Several synods held during the reign of Charlemagne sought to combat heresy and standardize faith and practice.