Leaving aside a number of Roman emperors that were far more powerful than Julius Caesar (let's just say that "Caesar" covers all of them as it was part of the standard imperial title) then at the very least Pope Innocent III, Pope Gregory I, and Pope Leo III were more powerful. For that matter, Pope Innocent III was more powerful than Julius Caesar and probably the second most powerful Italian ever after only the Emperor Augustus.
Oh, and definitely Pope Urban II as well.