In my last game, most of the major Christian rulers converted, including the Holy Roman Emperor. Catholicism survived with a few of the major dukes in France and the HRE, as well as the pope of course with his holdings in the Duchy of Cordoba. At the time of the end of the schism, the HRE was experiencing a major civil war between rival claimants for the imperial throne. The HRE recognized Patriarch Bardas, while the Duke of Aragon, the son of a deposed Kaiser, and his allies, the King of Lotharingia, the duchess of Brunswick, the duke of Swabia, and the King of Bohemia, supported Pope Donus II. Kaiser Theobald would've been deposed and Duke Mathias put on the throne, if it weren't for me, the new Roman emperor, joining Theobald in his war (a war, I should point out, I helped to instigate, so that I could more easily take territories from the Duke of Aragon that he had in Italy).
Catholicism lingered for a few more decades, thanks to its continued support in Lotharingia and in Spain, where the French and German dukes there remained Catholic. There was even a Catholic Holy Roman Emperor for a few years, but after two wars involving the Roman Empire (I joined factions that were fighting the Catholic German emperor), he was deposed.
By 1300 (where I stopped), 90 years after the end of the Great Schism, Catholicism is basically dead. The Byzantine/Roman Empire has conquered most of the areas that stayed Catholic in Spain and Italy. My zealous son, the Duke of Seville, has been revoking the titles of the Catholics there (a recently conquered territory taken directly from the King of France). The Pope is just some guy who lives in Rome.