The Basilica of San Petronio is the main church of Bologna, Emilia Romagna, northern Italy. It dominates Piazza Maggiore. It is the tenth-largest church in the world by volume and is dedicated to the patron saint of the city, Saint Petronius, who was the bishop of Bologna in the fifth century. Bologna Cathedral (Cattedrale Metropolitana di San Pietro, Cattedrale di Bologna), dedicated to Saint Peter, is the cathedral of Bologna in Italy, and the seat and the metropolitan cathedral of the Archbishop of Bologna. - Wikipedia