St. Peter's Basilica

The story of St. Peter's Basilica

St. Peter’s Basilica is the great Vatican church with a dome that dominates the skyline of Rome, and inside it is the largest church in the world by interior measure. It is also one of the holiest Catholic shrines, a major papal basilica, and part of the Seven Pilgrim Churches of Rome.

What you are standing in front of today is the present basilica, not the older church that came before it. The earlier St. Peter’s Basilica was begun by the Emperor Constantine the Great between 319 and 333 AD and stood over the small shrine believed to mark the burial place of St. Peter. By the end of the 15th century that old building had fallen into disrepair, and Pope Nicholas V first considered rebuilding it before Pope Julius II took up the project. The present basilica began on 18 April 1506 and was completed on 18 November 1626.

The rebuilding was one of the great architectural undertakings of its age. Donato Bramante’s design was selected first, and the foundation stone was laid in 1506. His plan was an enormous Greek cross with a dome inspired by the Pantheon, supported not by a continuous wall but by four large piers. Michelangelo later took over a site where four enormous piers were already rising behind the remaining nave of the old basilica, and Carlo Maderno also became one of the principal designers. Gian Lorenzo Bernini was responsible for the piazza and fittings. A surviving red chalk drawing from 7 December 2007, almost certainly by Michelangelo, shows part of the dome’s entablature above two of the radial columns of the cupola drum, and gives a rare glimpse into the working out of the design.

The building itself is a product of both Renaissance and baroque architecture, with materials listed here as cement and marble. Its measured size is immense: 220 metre long, 150 metre wide, and 136.6 metre high. If you look up at the dome, you are seeing the feature that defines the whole Vatican skyline. The basilica also contains the Loggia della Benedizione and the Tomb of Pope Leo XI.

The most important feature for pilgrims is below the high altar, also known as the Altar of the Confession. Catholic tradition holds that the basilica is the burial site of Saint Peter, chief among Jesus’s apostles and the first Bishop of Rome, and his tomb is directly below that altar. Many popes, cardinals and bishops have been interred here since the Early Christian period. In fact, there are over 100 tombs within St. Peter’s Basilica, including 91 popes, Saint Ignatius of Antioch, Holy Roman Emperor Otto II, Giovanni Pierluigi da Palestrina, Queen Christina of Sweden, Countess Matilda of Tuscany, and members of the exiled House of Stuart. The most recent interment was Pope Benedict XVI, on 5 January 2023. Beneath, near the crypt, is the recently discovered vaulted fourth-century Tomb of the Julii.

St. Peter’s has also had a major place in Catholic worship and history beyond burial. It is famous as a place of pilgrimage and for its liturgical functions, with the pope presiding at liturgies throughout the year in the basilica or in the adjoining St. Peter’s Square, drawing crowds from 15,000 to over 80,000 people. The basilica has also been tied to the Protestant Reformation and the Catholic Counter-Reformation. One method used to finance its construction was the granting of indulgences in return for contributions, and that campaign became bound up with the scandal associated with Johann Tetzel.

Today it is the most prominent building in Vatican City, wholly within the territory and sovereign jurisdiction of the Vatican City State, and it forms part of a UNESCO World Heritage Site. When you leave, the dome is the thing to keep in mind: it is the part of the basilica you can still see from far outside, and the clearest sign that this is the church’s defining structure.