Innocent III was known as one of the most powerful and influential popes in history. He was a major force in the Catholic Church during the Middle Ages and played a significant role in shaping its doctrines and policies. Some synonyms that can be used to describe him are: prolific, accomplished, formidable, imposing, and influential. The word "prolific" can be used to describe Innocent III's wide-ranging impact on the Church, while "accomplished" describes his many significant achievements as Pope. "Formidable" and "imposing" emphasize his strength and authority, while "influential" highlights his lasting impact on the Church and its followers.