a. the appeal of Christianity among all social classes of Europe.
Answer:
What helped Islam spread so quickly? I guess it kinda like your question
Explanation:
Muslim conquests following Muhammad's death led to the creation of the caliphates, occupying a vast geographical area; conversion to Islam was boosted by missionary activities, particularly those of imams, who intermingled with local populations to propagate the religious teachings. And I think that is how it spreads if any of that makes any sense!
