Pepin the short, Charlemagne father, was King of the Franks and annoited by the pope as divine leader. During his rule Pepin deported the Lombards from Rome. He pillaged their right to live in Rome. Then, he gave a large strip of Lombard land in central Italy to the pope. The pope now looked to the Franks as his protector. Then, in 768 Charlemagne became the Frankish king. At that time the Franks were falling back to barbarian ways like not caring about their education or religion. Europe was in chaos. The Saxons of northern Europe were still pagans. In the south the Roman Catholic Church was trying to assert its power against the Lombard Kingdom. Charlemagne was determined to bring Europe back to order by converting everyone to Christianity, making it be ruled by one government, and by educating people.
Charlemagne wanted all of Western Europe to become Christian. Charlemagne launched a campaign to conquer and convert the pagan Saxons. It was treacherous to be a Saxon. He did not want there to be any perfidy. His illumination was that if they did not convert they would be put to death. In one day he had 4500 Saxons killed. All the heathens were to become Christian or they would suffer the wrath of Charlemagne. He decreed that a tithe of all the produce of the land should be turned over to the church. He was able to enlarge his kingdom which was called the Frankish Empire. It included Germany, France, Northern Spain, and most of Italy. Now most all of Europe was finally ruled by one government, and Charlemagne was in control. Charlemagne wanted to revise learning because not many western Europeans could read and write. He established a palace school at Aachen to educate his officials. This school enabled western Europeans to have a common set of ideas.
Once Charlemagne tried to pay the Lombard King for the return of lands to the pope, but he refused so Charlemagne subdued, or subjugated his kingdom and restored the Papal States.