Why was Charlemagne hesitant about being crowned Holy Roman Emperor

Explanation: Charlemagne doubted being crowned emperor of the Holy Roman Empire because his superiority as Emperor before the Papacy was endangered, since being crowned by the Pontiff, the church was the one who granted him power, this would mean that his title as emperor was for under the authority of the Pope.

Charles Martel hesitated because at the time, the authority of the Pope could override that of the emperor. He would be crowned king of the Holy Empire, not the Empire itself. I hope this answers your question.