Well, I just made my first antipope--King Ugo I of Italy didn't appreciate Pope Clement II excommunicating him, and Clement II didn't appreciate Ugo whittling down the Papal States down to just Rome. (To be fair, it was Kaiser Rudger the Cruel who got Orbiettello for me, but the end results were the same.) Mind you, Ugo's participation in the Sardinian Crusade ended the excommunication, but he still didn't like the Pope very much. So, he instituted Free Investure in Italy, and set up the Bishop of Rialto as the new Pope, Honorious II. Having done that, he proceeded to die of old age, leaving the Kingdom to his son, Ugo II. Ugo II's project--get the Popes to know their place!