Charlemagne and Leo III
At the end of the eighth century, Pope Leo III sought the assistance of a king as he found himself in the middle of local warfare. Loyalists of the previous pope, Adrian I, wanted the ouster of Leo. They accused him of all sorts of corruption, including adultery and perjury. Leo's enemies then kidnapped him and hid him in a monastery in Greece. He was rescued, but the unrest did not stop there. Street fighting broke out amongst the people of Rome, and with no emperor in the Western Empire, Leo found he needed some outside assistance. He would certainly not turn to a woman—Empress Irene, who ruled over the Eastern Empire—so he called upon Charles, the King of the Franks, a long-time supporter of the papacy.
King of the Franks
He was called Charles the Great, but you may know him as Charlemagne (a name he was given by later generations). Charlemagne first stepped into the spotlight of Christian history when he traversed the Alps to Rome, where he intended to put an end to the city's troubles.
On December 23, A.D. 799, Leo took an oath on the holy Gospel that he had not committed the crimes of which he was accused, and Charlemagne added his stamp of approval—declaring to the world that Leo was innocent of all charges.
The reason Charlemagne was so readily accepted by the Western Empire goes back to his grandfather, Charles Martel, or Charles “the Hammer.” He was renowned for saving the kingdom of the Franks from the invading Muslim armies. Later, the pope declared Charles' son, Pepin the Short, the King of the Franks, which was the beginning of an amicable relationship between the Franks and the Romans.
The next day, on December 24, at a Christmas Mass, Leo crowned Charlemagne emperor. The congregation cheered as Leo knelt before the king. This was the first time in history that a pope had appointed an emperor—a symbolic gesture for the future of the empire and the papacy. Charlemagne had restored the Christian Roman Empire (Holy Roman Empire) and was declared on that day to be a great and peaceful leader—a reputation that he would carry through the Middle Ages to modern times.
By using Augustine's The City of God as his reference, Charlemagne was responsible for pulling the Catholics together again. Who knew that one monk's scholarly effort could have such tremendous influence over an entire religion for centuries to come?
As King of the Franks, Charlemagne had three goals in mind:
He wanted enough military power to follow in his grandfather's footsteps, with the ability to crush any threatening enemy.
He wanted the religious power to guide the souls of his people.
He wanted enough intellectual strength to teach people to nurture both mind and soul.
Charlemagne was successful in his vision, and as a result, established a new political order for Europe under the jurisdiction of the Catholic Church. As emperor, Charlemagne had the same vision for Christendom as he did for the Franks of his own kingdom: He wanted to present the world with a unified society of Christians mingling the eternal with the temporal. In other words, Christendom would be a cohesive society that blended the spiritual truth with earthly (or political) matters.