8 Things to Know about Bologna’s Basilica of San Petronio

The Basilica of San Petronio stands on Bologna’s main square, Piazza Maggiore, and is likely to be one of the first sites you’ll visit in town. It is the Bolognesi’s most beloved church, a symbol of the city today as it was in the past, when it was used as a public space rather than a merely religious one.

Here are eight interesting things to know about San Petronio (as we Bolognesi simply call it) to enhance your visit.

1. Despite being Bologna’s most important church, San Petronio isn’t the city’s cathedral, which stands nearby on via Indipendenza (the Duomo di San Pietro). It’s dedicated to the patron saint of the city, Petronius, who was the bishop of Bologna in the 5^th  century. On the side of the Basilica on via dell’Archiginnasio, look for the inscription outside the chapel that houses the saint’s relics, which reads: Felsinae Thesaurus, the treasure of Felsina (Felsina is the Etruscan name of Bologna).
2. San Petronio is one of the world’s largest churches (the sixth largest in Europe): it’s 132 meters long, 60 meters wide and 45 meters high. Construction began in 1390, based on a project by architect Antonio di Vincenzo. Work on the basilica continued for centuries, with a second project presented in 1514 envisioning a building that would measure 224 meters in length and 150 meters in width, bigger than St. Peter’s in Rome. But the Catholic Church would not see to that. Still, San Petronio truly feels grand and you’ll fully realize how big it is only when you go inside.

3. The Basilica of San Petronio is unfinished. This is obvious when you look at the façade: the bottom part features white and red marble (the colors of the city), but the upper part is just bricks. In addition, the original plan, which called for a gigantic cross-shaped building, was never brought to completion; when, in 1562, the Catholic Church ordered the construction of the Archiginnasio, the first official seat of the University of Bologna, on the space adjacent to the basilica, the original projects had to be downsized.
4. The Basilica of San Petronio was not intended as a church, but rather, as the name suggests, as a public space, a civic temple (the word ‘basilica’ originally indicated an ancient Roman building where official and public functions took place); the project was approved by the local city council in 1388 when Bologna was a comune proud of its independence, and was meant to highlight the city’s prestige, as well as glorify the figure of Petronius. Just consider that the property of the basilica was not transferred from the city to the diocese until 1937, and the church was not consecrated until 1954.
5. Serving its functions of public space, the Basilica of San Petronio hosted a seminal event of the 16^th century: the coronation of Charles V to Holy Roman Emperor by Pope Clement VII on February 24, 1530. A plaque outside the first chapel in the left nave remembers the event, which attracted thousands of people to the city. Bologna was at the time the second most important city of the Papal States, after Rome; in the 16th century, the basilica also hosted the Council of Trent.

6. The three portals on the façade are graced by small sculptural masterpieces many visitors miss. The central door features sculptures by Jacopo della Quercia depicting prophets and stories from the Bible, as well as a Madonna with a Child, Saint Ambrose and Saint Petronius. Jacopo della Quercia’s innovative, ‘muscular’ style, would influence none other than Michelangelo, who spent some time in Bologna as a young man (leaving the city with three sculptures found in the Basilica of San Domenico). The right and left portals feature bas-reliefs by Amico Aspertini, Alfonso Lombardi and Properzia de’ Rossi, one of the rare female sculptors of the Renaissance.
7. The Basilica of San Petronio houses the longest indoor meridian line in the world, measuring 66.8 meters. Inlaid in the paving in the left nave, it was designed in 1656 by Italian astronomer Gian Domenico Cassini, a professor of astronomy at the University of Bologna. It corresponds to 1/600,000 of the Earth’s circumference. It allowed for more precise astronomical observations and, to this day, it marks the passing of days and seasons, with the sunray entering from a hole positioned in the vault 27 meters above the ground and hitting precisely the line.
8. Cappella Bolognini, or of the Magi, one of the 22 chapels of the basilica, houses one of the most original depictions of Heaven and Hell, painted by Giovanni da Modena and inspired by Dante’s Divine Comedy. The Inferno is dominated by a gigantic figure of Lucifer, and facial expressions are all dramatically accentuated. Just imagine what feelings of terror the fresco must have inspired to most people, who, at the time, could not read or write. (There’s an entrance fee of 3 euros to visit the chapel).

The Basilica of San Petronio is open every day from 7.45 am to 2 pm and from 3 pm to 6 pm. Entrance is free, but there’s a fee of 2 euros for taking photographs.