Gregory I increased the political power of the pope because he reformed and rewrote some of the aspects which were expected of the papacy, but which were things he did not want to do anymore. Upset by the privacy he used to have as a monk but which he no longer had anymore, he set out to involve himself more in the larger population's life by sending missionaries to England and by writing dialogues commenting on many different things. He also reformed and revised Roman worship of his day, which included more political power for the pope.
because his empire spanned across an ocean it made it hard for his subjects to be directly under him, and hard to maintain a tight grasp on his empire, making the enforcement of catholicism harder as well
