Recently I conquered Rome in a game of mine with Sicily. The pope had just moved 2 full stacks eastwards and now, having regained Rome, Also holds Constantinople and a few surrounding territorys despite pressure from the Turks and the remaining Byzantines.

Also, the pope dies, im re-patriated with the church with 1 cross standing. 2 more popes go through and suddenly I have 6 cardinals including one of the Priest Preferati and full standing with the church (I lost Rome to a spanish crusade). The pope tends to forget quite easily :)