The Basilica of San Petronio is a minor basilica and church of the Archdiocese of Bologna located in Bologna, Emilia Romagna, northern Italy. It dominates Piazza Maggiore. The basilica is dedicated to the patron saint of the city, Saint Petronius, who was the bishop of Bologna in the fifth century. Construction began in 1390 and its main facade has remained unfinished since. The building was transferred from the city to the diocese in 1929; the basilica was finally consecrated in 1954. It has been the seat of the relics of Bologna's patron saint only since 2000; until then they were preserved in the Santo Stefano church of Bologna.