Quote Originally Posted by Basilakes En Strategoisin
I'm confused - so how do you tell, playing as Byzantines/Muslims, which Catholic factions are excommunicated and which aren't

That's just it, you can't. It's a fairly safe bet if a catholic faction is at war with 3-4 other catholic factions all at the same time (actively at war, meaning fighting battles all the time) then it has been excommunicated.

Well, Temujin, I was at war with Venice and Hungary most of the early part of my Byzantine campaign too. Venice started it by marching in and besieging Thessalonica. I relieved the siege, which caused my relations with the Papal states to drop. They'd blockade a port, I'd break the blockade, and my Papal States relationship would get worse. The only time I didn't have a lowering when I attacked one of their units was when I was pretty sure they were excommunicated.