The Basilica di San Petronio is regarded as the main church of Bologna city and is the fifth largest church in the world. This building can contain over 28,000 people at a time. This church is dedicated to the patron saint of the city, Saint Petronius, the bishop of Bologna in the 5th century. The first stone construction was laid down in 1390. This historic building was lastly completed in 1646 to 1658 by Girolamo Rainaldi.