Question

How did the Catholic Church promote Charlemagne's right to rule?

The pope sold Charlemagne an indulgence that allowed for his ascendance as emperor.
The church stated that Charlemagne was a physical manifestation of God on Earth and was appointed by God to rule.
The church appointed Charlemagne the head of Vatican City.
The pope issued a papal bull that Charlemagne shared with the Franks at a feast during his coronation.

Answer 1

The church stated that Charlemagne was a physical manifestation of God on Earth and was appointed by God to rule.

Answer 2

The church stated that Charlemagne was a physical manifestation of God on Earth and was appointed by God to rule.

Step-by-step explanation:

The Alliance between the Church and Charlemagne made the Catholic church stronger and its kingdom. From this alliance, the Holy Roman Empire was born, which meant that the Catholic Church pointed out that Charlemagne was a Christian king appointed by God to protect and promote the church.