Nobody knows? Hm, perhaps I was not specific enough.
I'm playing as Venice and I got the "vassalize Roma" quest. I did vassalize it, and then I got the quest to integrate it.
Now, I know from my previous games that if Roma gets annexed I have a high chance to get the quest "Restore the Holy See" (as long as I remain Catholic, that is).
What I want to know is if forming Italy (thus moving my capital to Roma) would prevent this quest from triggering for other nations.
I'm really not in the mood fighting Castile, France and/or Austria.