Charlemagne was a devout Christian who set out to improve the church. When the pope’s rivals planned to take him out, the pope fled into Charlemagne’s empire and received safety from his court, then went back to Rome when the time was right. Charlemagne supported the pope, and their relationship led to Pope Leo III crowning Charlemagne emperor in a coronation.
I have supreme authority
This coronation strengthened the power of the Church in western Europe by establishing the principle that only the pope could crown an emperor. Yet, the people had mixed views on religion. Therefore, this led to a split between the Eastern Orthodox and Roman Catholic churches.
You don't have the right to do that. I appoint the bishop.
I've appointed a bishop
Charlemagne believed that God had made him emperor in order to do God’s work on Earth, it was the duty of the pope to assist him. The pope believed that the church made Charlemagne emperor, and it was the duty of the emperor to assist the Church in doing God’s work. Some 200 years after Charlemagne's coronation, different views led to a dramatic clash between an emperor and the pope.
Would you like to sign a treaty. It is called the Concordat of Worms
Yes, that would be great!
In 1073, Pope Gregory IV issued a list of rules declaring his supreme authority over both church and secular leaders. In return, Henry IV, the holy roman emperor at the time was upset. He started a clash of wills between the two, because the new rules were a direct attack on his own power and rights.
The conflict was that Henry ignored the popes rules and appointed his own bishop for the city of Milan, Italy. Then, Pope Gregory appointed a rival bishop and Henry tried to remove Gregory as pope. The Pope then excommunicated Henry. And freed his subjects from feudal oaths. The people across Europe then took sides.
Conflict eventually ended in 1122, when the church and the holy roman empire reached an agreement they called the Concordat of Worms. This agreement gave the church the sole authority to appoint bishops and also allowed emperors to give fiefs, grants of land, to bishops to win their loyalty. Yet, despite the agreement, popes and rulers continued to have conflicts.