Histories of the Papacy

I’m planning to read a history of the papacy this summer. I already own two: Nicolas Cheetham’s History of the Popes, and Roger Collins’s Keepers of the Keys of Heaven. (I also own a more general (and longer) history of Christianity, Diarmaid MacCulloch’s Christianity: The First Three Thousand Years.) Does anyone have recommendations as between the two papacy books, or the three Christianity books?