In my groups campaign back when i was in the navy, we actually had the pope who succeeded Pope John Paul II was an East German preist. He was much younger than anyone would have thought (he was 32) since the cardinals felt they needed a young and vibrant Pope... This new Pope (i can't remember the name he chose for his regin) expanded the military forces that had been loyal to the Papal States. In fact he did alot more than just this. He adopted reforms of the priesthood (such as allowing priests to marry among the biggest and most controversial change), he also used the resources of the Catholic Church to establish Papal States around monestaries and cathedrals and the like....
This had alot of things happening in the campaign, especially since the leader of the biggest unit of the 'Polish Free Legion' was a Priest... It was through him that the GMs would provide information about what was going on around the world. Especially since the Papal states had their own communications and transport networks.
Yeah, we had an all-powerful Roman Catholic church in our campaigns.
We felt that there just had to be a major mover-and-shaker out there that had the resources that caused everyone else (including marauders) to think twice about pissing off...
When we played the 'Going Home' module, the Church wasn't to happy with how the French had occupied Belgium & Luxembourgh, half of the Netherlands and the Rhineland while turning a huge swath of the east bank of the Rhine into a dead zone. It was through the chuch who was allowed to go into the terrified German communities that was under martial law imposed by really violent French soldiers who blamed everything that had happened on Germany. It was because the Church had kept informing the British Army of the Rhine of what was going on in the occupation that the Anglo-American forces coming to Bremerhaven was ready for the 'sneak attack' that the french had planned on launching to destroy the surviving forces of the US European Command.
When the dust settled the Germans got back the Rhineland, Alasce-Lorrane was merged with Luxembourgh to create a buffer state seperating France and Germany, the Flemish portion of Belgium became the Republic of Flaners, and the German community of Belgium becomes part of the Netherlands.
Thus the majority of the forces assigned to US European Command had withdrew from Europe and headed back to the US after their last major battle. This also gave a reason for some to remain in Europe to oversee those forces who couldn't get to Bremerhaven (those forces still out in the field surrounded by hostile forces). And it also allowed us to set up the framework for when the 'Return to Europe' modules came out.
But I degress... Back to the Papal States.
Our campaign had Italy breaking into three states... Northern Italy became the Republic of Tuscony, Southern Italy and the islands of Sicly and Sardenia retained the name of the Italian Republic. But the the central provinces of Italy became the Papal States, with their capitol being the Vatican. The Papal states where protected by the Papal Self-Defense Force, made up of the Swiss Guards, and other historic military groups that where recommissioned by the Pople to protect the Church and its people.