Complex sentence: Peter of Angoulême was reconciled with the legate, excommunicated Bohemond and the Commune, and then persuaded some nobles to rise up against Bohemond, forcing him to take refuge in the citadel.
Split into simpler sentences: Peter of Angoulême was reconciled with the legate and excommunicated Bohemond and the Commune. He also persuaded some nobles to rise up against Bohemond, forcing him to take refuge in the citadel.