How to Unlock the Papal States in "Medieval II: Total War"by Seth AmeryUpdated September 22, 2017
Though you unlock most of the in-game factions after you've completed a campaign in "Medieval II: Total War," the Papal States aren't one of them. The Papacy is meant to be a non-playable faction, but you can still unlock it the same way as the other factions.
Unlocking the Papal States
Navigate to the "Medieval II" installation folder. Steam copies appear in the same format as other Steam games, while non-Steam copies install to C:\Program Files\SEGA by default. Continue on to data\world\maps\campaign\imperial_campaign and open descr_strat.txt in Notepad. Move "papal_states" from the Non-playable category to Playable. Save your changes and reload your game to pick the Papal States from the Campaign menu.
Playing the Papacy
As this faction, you start with only Rome and must conquer at least 80 or 100 cities to win the campaign, depending on length. Because you're not supposed to play the Papal States, gameplay can be unstable. For example, while you could still face excommunication for attacking your Milanese and Sicilian neighbors, they don't have repercussions for striking first.