I once played as the duchy of Milan. I was allied with the pope. My council gave me the order to free the city of Florence of that pesky rebels. Of course i take that beautiful city. Two turns later that expansionist swine in Rome marched with his army to Florence and besieged it!

Results: excomm, a very long and bloody war against half europe, and a bitter dislike for his hatness

Don`t talk about passive pope, he is an Machiavellian expansionist