He united most of Western and Central Europe , and was the first recognised emperor to rule from the west after the fall of the Western Roman Empire approximately three centuries earlier. Charlemagne's reign was marked by political and social changes that had lasting influence on Europe throughout the Middle Ages. With his brother, Carloman I , he became king of the Franks in following Pepin's death and became the sole ruler three years later. Charlemagne continued his father's policy of protecting the papacy and became its chief defender, removing the Lombards from power in northern Italy in His reign saw a period of expansion that led to the conquests of Bavaria , Saxony , and northern Spain , as well as other campaigns that led Charlemagne to extend his rule over a large part of Europe.
Charlemagne spread Christianity to his new conquests often by force , as seen at the Massacre of Verden against the Saxons.
He also sent envoys and initiated diplomatic contact with the Abbasid caliph Harun al-Rashid in the s, due to their mutual interest in Iberian affairs. Although historians debate the coronation's significance, the title represented the height of his prestige and authority.
Charlemagne's position as the first emperor in the West in over years brought him into conflict with the Eastern Roman Empire in Constantinople. Through his assumption of the imperial title, he is considered the forerunner to the line of Holy Roman Emperors , which persisted into the nineteenth century. As king and emperor, Charlemagne engaged in a number of reforms in administration, law, education, military organisation, and religion, which shaped Europe for centuries.
The stability of his reign began a period of cultural activity known as the Carolingian Renaissance. Charlemagne died in and was buried at Aachen Cathedral in Aachen , his imperial capital city. He was succeeded by his only surviving legitimate son, Louis the Pious.
