Questions about Medieval II Total War

[Onasander]

I haven't played this game in years, just got it in the mail.

 

I'm playing the Venetians, and have a bit of a empite, but the pope excommunicated me. I'm under siege in Damascus by the Mongols, and crusaders keep showing up in Constantinople, despite my holding Sophia/Sofia (however it is spelled) and every country west of Milan and Genoa keeps shoeing up.

 

I have/had a near complete monopoly on the cardinals, but the Vatican is all pooie right now, rarely promoting mine.

 

I vaguely recall years back solving this issue by storming Rome, but if I recall it doesn't kill off or subjugate them, but rather pisses them off more, I had to give the Carthage back then to be nice again.

 

Is there anything I can do to make the Vatican start liking me again? I can't even recall ever trying to assassinate the pope, so don't much know if it is possible.

 

If my cardinals are excommunicated, I don't understand how they occasionally get promoted. Will I get to vote in the next elections, or permanently out till hell freezes over? They should be nicer to me, as I'm the only one converting the Turks and Egyptians.

 

Also, I recalled playing the Byzantines. I think all I gotta do is complete the campaign and they are added, right?