On Piazza Maggiore, opposite the Palazzo del Podestà, the Basilica di San Petronio begun by Antonio di Vincenzo (1390), is the largest structure on the square—yet, had the Bolognesi had their way, this temple to their most important patron saint would have been far, far grander, and even larger than St Peter’s in Rome. An entire city neighbourhood, eight other churches and countless towers were cleared for the site, but that wasn't enough. The Bolognesi constantly remind us that Pope Pius IV himself, in 1565, ordered that the money be spent instead on the university’s Archiginnasio, instead of on municipal prestige.
As it is, San Petronio is the fifth-largest church in Italy and the fifteenth largest in the whole world (132m by 60m), and the Pope’s decision may have been less maintaining Rome’s bragging rights than simple economy. Or it might have been aesthetics; if the models inside are any indication, Pius might well have saved Bologna a very large, marble-coated civic embarrassment. The white and red marble stripes, recalling the city’s heraldic colours, only made it up to the level of the portals. Imagine them covering the entire building, and you would have something almost as eccentric as Florence’s Duomo, which has been memorably described as ‘a cathedral wearing pyjamas’.
Bologna was so miffed by the Pope’s decree that in over 400 years it has never even bothered finishing the Basilica’s façade. Italian cities have any number of bare, brick-front churches, testaments to exhausted ambitions or civic disasters, but this is the most conspicuous, although even some of Italy's greatest architects, including Vignola and Palladio, submitted design proposals. Even staid old Florence felt sufficiently embarrassed finally to tack up a façade for its Duomo in 1888. But not Bologna. Somehow, San Petronio’s grimy cliff-face is very Bolognese, a disregard for appearances that says ‘Love me as I am’.
Like St Mark's in Venice, San Petronio was a civic project that had little to do with the powers that be in Rome. It was the venue for all the solemnities of Bologna's Senate, and was only given to the diocese in 1929, and only consecrated in 1954. In 2000, the relics of Petronius were finally transferred here from Santo Stefano.
The façade does have a remarkable portal, with a stately Madonna surrounded by reliefs of Old and New Testament scenes and prophets by Jacopo della Quercia, begun in 1425. Like Ghiberti’s doors to the Baptistry in Florence (for which job della Quercia had been one of the unsuccessful candidates), they are landmarks in the visual evolution of the early Renaissance, and seem strangely modern – almost Art Deco in sensibility. Amico Aspertini sculpted the central arch; Alfonso Lombardi contributed the Resurrection (left door) and the Deposition (right door).
Missing from the front of San Petronio, however, is Michelangelo’s colossal bronze statue of Pope Julius II, commissioned by that pope in 1506 after he regained the city for the Papal States. Julius also commissioned a large castle in the centre of Bologna. Both were torn to bits by the population as soon as the pope’s luck changed; and to rub salt into his wounded pride the bronze was sold as scrap to his arch-enemy, Alfonso I of Ferrara, who melted it down to cast an enormous cannon.
The lofty, spacious interior was probably built much as architect Antonio di Vincenzo imagined it. It saw the crowning of Charles V as Holy Roman Emperor by Pope Clement VII in 1530. This would be the last papal coronation of an emperor, but perhaps it was one too many. According to local tradition, it occasioned the conversion of a visiting monk named Martin Luther, who became so nauseated by papal pomp and pageantry that he decided to go home and start the Reformation.
In 1655, while teaching astronomy at Bologna University, Giovanni Cassini (future royal astronomer to Louis XIV in Paris) traced a meridian on the floor of the basilica and designed the huge astronomical clock which marks noon and tells the hour of sunrise and sunset with the shaft of light admitted through a small aperture in the vaulting at noon (solar noon, not clock time). Cassini’s meridiana is the longest in the world in a closed space, exactly 1/600,000 of the earth’s circumference, and the length of the shadow on it also tells the date. An optical illusion makes the image of the sun look heart-shaped, if you see it at just the right time on certain days of the year; seeing the illusion has always been taken as good luck for newlyweds. The meridiana isn’t just a toy, though; creating it was serious work that helped to precisely determine the movements of the earth, necessary for Pope Gregory’s 17th-century calendar reform. It also helped to prove the earth wasn’t the centre of the universe.
Around the nave you’ll see four carved crosses, set atop antique columns. These once marked the four gates leading into the city; according to local legend they were placed there by Petronius, or else St Ambrose, as part of a magic circle that protected the city (actually they are 8th-century, and typical of the crossroads monuments common throughout medieval Emilia).
Many of the chapels hold fine works of art. The first on the left (Chapel I), was the site of Charles V’s coronation in 1530 and has some exceedingly strange (and exceedingly bigoted) frescoes by Giovanni da Modena on the Triumph of the Church over the Synagogue and the Redemption of the Original Sin. Chapel II was designed to house St Petronius’s head; in Chapel III you’ll find the Madonna of St Luke with SS Emidio and Ivo by Gaetano Gandolfi and Alessandro Tiarini’s Apparition of the Virgin to St Francesca Romana. The clocks hanging on the adjacent pillar date from 1758 are said to be the first in Italy with adjustable pendulums
The famous Chapel IV, the Cappella Bolognini (Cappella dei Re Magi) stands next to a giant figure of St Christopher. It was frescoed by the same Giovanni and his assistant, Jacopo di Paolo (1415). In his will, Bartolomeo Bolognini provided the funds and requested a Paradise, which was interpreted by Giovanni quite intentionally to resemble a Church Council, with rows of saints seated at benches, gazing raptly at the Coronation of the Virgin.
But Bolognini's will also stipulated an Inferno 'as horrible as possible'. Giovanni duly filled his craggy underworld place with one of the most dramatic, most populous Last Judgement scenes ever painted, full of interesting detail, much of it taken from Dante: there's a Heaven painted with allegorical figures of the Seven Deadly Sins, a Wood of the Suicides, and a Devil with two mouths (one in the nether regions), one devouring Judas, the other Brutus – sacred and secular treachery are damned equally.
He also placed (and labelled) Mohammed as an elderly man just to the right of Satan, bound to a rock and tortured by a demon. His presence in Hell wasn't unusual in medieval art (Dante placed him there among the ‘Sowers of Discord’ in his Inferno) but it has seen the basilica getting some unwanted notoriety. In 2002 and 2006, plots to blow up the basilica by Muslim terrorists who claimed the art was insulting to Islam were thwarted by the police. Islamists in Italy are still calling for the fresco to be destroyed, and the police keep a close watch on it—which explains the metal detectors newly installed at the basilica's doors.
Bolognini also specified scenes of the Legend of the Magi, but didn't say which journey, so Giovanni, chose to depict the three kings sailing home after their visit to Bethlehem. Other scenes in the chapel are on the Legend of St Petronius, which show the Bologna of the early 15th century. One, depicting the installing of a bishop by the anti-pope John XXIII, allowed scholars to date it c. 1412-20. The stained glass was designed by Jacopo di Paolo.
Chapel V has an Annunciation, with the Virgin by Lorenzo Costa and angel by Il Francia. Costa also painted the Twelve Apostles, and Madonna Enthroned with Saints one of his finest works, in Chapel VII. The latter, formerly belonging to the Baciocchi family, contains the tomb of Elisa Bonaparte, the only one of Napoleon’s sisters who had any actual political powers, as the the Princess of Lucca and Piombino, and later Grand Duchess of Tuscany; she is buried with her husband, Prince Felice Baciocchi.
Chapel VIII has a San Rocco by Parmigianino, one of the few paintings by the most elegant of Mannerists in Bologna, while Chapel IX has an Archangel Michael defeating the Fallen Angels (1582) by Donato Creti and a bust in terracotta of Andrea Barbazza by Vincenzo Onofri (1479). Chapel X, the chapel of the city of Bologna, has a Martyrdom of St Barbara, by Alessandro Tiarini.
Over the high altar is the Tribuna, supported by columns of Verona’s famous red marble designed by Vignola, with an enormous 15th-century Crucifixion . A large fresco of the Virgin, Child and St Petronius fills the apse, overlooking a set of 15th-century intarsia choir stalls by Agostino de’ Marchi, featuring large figures of SS. Petronius and Ambrose by Francesco del Cossa.
The altarpiece in Chapel XIV boasts a statue of St Anthony of Padua, attributed to the great Renaissance sculptor architect Jacopo Sansovino; on the altar of Chapel V, is a throne by Alessandro Algardi, sculpted from ancient Roman marbles. Chapel XVII has another work of Costa, St Jerome; Chapel XVIII houses Amico Aspertini’s Pietà.
In the Museo Storico (entrance to the left of the high altar) are some of the instruments Cassini used to lay out the Meridiana, and drawings and models of some of the grand schemes for the church and its facade. It also has nine illuminated choir books used by the Cappella Musicale.
For centuries San Petronio was renowned for music. The Cappella Musicale, founded by Pope Eugenius IV in 1436, initially had a singing master and 24 boy clerics singing plainchant, although within a few years paid performers were added. Gradually they moved towards polyphony, with two choirs accompanied by various instruments: a new organ in 1476, and then another, facing it, in 1596 (both were restored in 1974-82 and remain in excellent working condition). Trombones, cornets, strings, bassoons, oboes, a theorbo (a long-necked lute) and serpents (a curly ancestor of the tuba) were added.
By the early 17th century, the Cappella regularly employed 42 musicians, with as many as 150 extra singers and musicians added for the most important occasions. Large scale, complex compositions, featuring up to nine soloists, were especially written for San Petronio (where the harmonic possibilities were somewhat limited in extremely long 12 second reverberations in the enormous church) by its great maestri di cappella who formed the core of the Baroque Bolognese School of Music: Maurizo Cazzati (1657–71), Giovanni Paolo Colonna (1674–95) and Giacomo Antonio Perti (1696-1756).
In the 19th century, the Cappella Musicale slowly declined, only to be completely abolished in 1929. But in the 1980s it was revived, with the mission of studying and reviving works from San Petronio's Renaissance and Baroque glory days. It was the first orchestra in Italy to use original instruments, and it performs in the original choir setting in San Petronio and all over the world, recording with Bongiovanni, Dynamic, Harmonia Mundi France, Naxos and Tactus.
Hours Basilica: 7.45am-6.30pm. Cappella dei Magi: 10am-6pm. Museum: Tues-Sat 10am-12.30pm and 3-5.30pm; Sun 3-5.30pm. Closed Mon.
Adm Free. For security reasons, avoid bringing along large bags or backpacks. Cappella dei Magi €3. Museo €3.
+39 051 231415
Images by: Università degli Studi, g.sighele, PD Art, Basilica di San Petronio