Pius VII is elected pope. When he is crowned in a few days, he will have to use a papier-mâché tiara because the original papal crown has been removed from Rome by French forces when they took Pope Pius VI prisoner.
The first new pope of the 19th century, Pius VII is elected as a compromise candidate - he's not the first choice for any of the cardinals at the conclave, but picking him breaks a stalemate among cardinals divided into nationalistic factions.
Most of the reign of Pope Pius VII will involve conflicts with France. He tries to develop a working relationship with Napoleon, but like his predecessor he's taken prisoner in 1809 and exiled to Savona.
After his release, he reinstates both the Inquisition and the Index of Prohibited Books, brings back the Jesuits, and condemns the Protestant Bible Societies. This makes Pope Pius VI the first modern pope to specifically condemn and fight against modern developments in politics, religion and philosophy.