In 799 The Pope came to Charlemagne and had a coronation with him. He crowned him the ruler of Europe. This was always Charlemagne's dream to be the ruler of Europe.
Then in 1073 Pope Gregory was in charge and made changes that destroyed the emperor which was Henry IV at the time. The three most important changes was that he had supreme authority over the nonreligious, made the Pope the only one able to choose a bishop and claimed the power to change who the emperor was.
I am so sorry for what I did to you...
Henry the IV was not happy about what Pope Gregory did. At that time Henry IV was not happy with this. Everyone new that their was going to be a big clash between the two.
It first started when Henry IV ignored the pope's rules and named his own bishop for the city. Then Pope Gregory brought in a new bishop.Then the Pope kicked out King Henry out of the church.
People then took sides. Henry IV was called in and had to wait for 3 days in the snow. Then after the Pope forgave him for what he did to him. But Henry IV did not forgive him and took charge from the pope.
Then in 1122 long after both of them died the two sides made a agreement called the Conduct of Worms. It made Pope's able to pick bishops. It allowed emperors to give fiefs, or grants of land, to bishops in order to win their loyalty.