Charlemagne (742/747/748-814), also known as Charles the Great or Charles I was the eldest child of King of the Franks, Pepin the Short. He took the Frankish throne after his father's death in 768, initially co-ruling with his brother Carloman I, who died in 771, leaving Charlemagne as undisputed ruler of the Franks. Charlemagne considered himself a protector of the papacy, and invaded northern Italy to remove the Lombards from power, becoming King of Italy in 774. He also led incursions into Muslim Spain and campaigned against the Saxons of the east, Christianising them upon penalty of death, resulting in events such as the Massacre of Verden. Uniting large swathes of Western Europe during the early Middle Ages, Charlemagne reached the height of his power when he was crowned 'Emperor of the Romans' in 800, recognised as the true successor of the Roman emperors of old. Now ruling as Holy Roman emperor, Charlemagne's conquests instigated the Carolingian Renaissance, a period of enlightenment and cultural activity for the Western Church. The Byzantine Empire and the Eastern Orthodox Church viewed him more controversially however, with Empress Irene actively supporting Charlemagne's rivals. Charlemagne eventually died in 814, ruling as emperor for just over thirteen years, and was laid to rest in his imperial capital of Aachen, in modern-day Germany. He is often called the 'Father of Europe' (Pater Europae).