They would have been fighting each other
Answer: Charles the Great.
Explanation:
Charlemagne has crowned Christmas in 800 AD. The ecclesiastical question was the most important in Europe in those decades, and Charles the Great was the most capable ruler in Europe.
Consequently, the pope turned to the ruler of the enormous European Empire at that moment. Some historians also call him the "Greatest Christian of all time."
To see if they are trying to provide bias or persuade or be one-sided in their claims. Also to know what was their purpose of providing the evidence was for. The author put in the time and effort to create the source so what was his end goal to accomplish for the reader.
