Hadrian the Seventh

This amusing 1904 novel about a renegade pope is timely. Dan Fox provides a good summary of the plot:

Hadrian the Seventh tells the story of George Arthur Rose, an unashamedly transparent avatar for Rolfe. The chain-smoking Rose is a failed writer, living in poverty in a London garret with no one other than his imperious cat Flavio for company, and nursing bitterness at having been rejected from the Catholic priesthood. 

One night he is visited by two envoys from the Vatican, including a Cardinal Archbishop. They inform him that the Papal Conclave has been in session to elect a new Pope, but the discussions have reached stalemate. By a strange twist in events, the Conclave has decided to offer the Papacy to Rose, which he accepts, taking on the name Hadrian VII in homage to Nicholas Brakespear, the last and only English Pope, Hadrian IV, in the 12th century.

Rose travels to Rome and, once ordained, sets about exacting revenge against every person and institution that has ever crossed him or disagrees with him, and dragging the Roman Catholic church through a set of reforms. 

Pope Hadrian wants to redesign the crucifix, re-decorate the Vatican and redraw the boundaries of various European nations. Oddly, his decrees do not include lifting the church’s ban on homosexuality, and Hadrian rails against socialism despite deciding to re-distribute the Vatican’s wealth to the poor. The story ends with Rose assassinated by an anti-Catholic Scotsman. 

See also the excellent Quest for Corvo.