Quote Originally Posted by English assassin
I think I have had times when I've been attacked by a faction against whom I have a warning, defended myself WITHOUT leaving the province that was attacked, and been excommed.
Hmmm...
Do you have any unresolved sieges? And was that province (which was attacked) previously owned by the attacking faction??
Also, maybe you attacked after the two year period and within the ten year period. That would excomm you instantly...

I see the thing with excomms like that it grants the defender a "right" to reclaim lost provinces. If defender reclaimed a lost province, the attacker cannot "rereclaim" it for himself without being excommed. I must say that excomms have flavoured the game considerably, and that is one of the greatest things CA has done in this game. It fits perfectly in the given setting and it changes the game mechanics to a whole new level.

It's a piety though, that because of the fear of being excommed, I seldom get to fight a battle. I just surround the target I'm after from neighbouring provinces and/or sea and overwhelm it. The AI then either:
a) retreats all of his armies in a single province that I can't reach, or
b) fights with me one small desicive battle which I always win.
If he retreats to a single province or two, I can keep the short border with my whole army while some of his die in the sieges. Then he just sits in that one province fearing to reconquer what is lost, because he can't guard more than one province - I'll then invade both of them.

Unfortunately, wars are won on the strategic map more often than not. It all comes down to blitzin' the AI to some remote province you can easily guard.