St. Peter’s Basilica Architecture

A Guide to Understanding the Unique Architecture of St. Peter's Basilica

Standing tall as a mark of Rome and the entire Christendom, St. Peter's Basilica in the Vatican is a Renaissance masterpiece. Built over the Tomb of St. Peter, one of the twelve apostles of Jesus Christ, the colossal structure is one among the four major basilicas in the world. Learn about everything that makes this Church an architectural marvel on this page.

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Official Name: St. Peter's Basilica, Basilica di San Pietro

Status/Function: Church

Location: Piazza San Pietro, 00120 Città del Vaticano, Vatican City

Founded: 1626

Area: 220 metres (length), 150 metres (width), 136.6 metres (height)

Architectural Style: Renaissance and Baroque

Main Architects: Donato Bramante, Maderno, Raphael, Michelangelo, Gian Lorenzo Bernini

History of St. Peter's Basilica Architecture

St. Peter’s Basilica Architecture

St. Peter's Basilica, when completed in 1626, was hailed as the greatest building ever constructed. It was particularly noted for its Renaissance and Baroque style. The Church you see today was built after razing the Old Basilica that stood in its place for over 12 centuries. 

The current St. Peter's Basilica, like the previous Church, was built to commemorate St. Peter, the first Bishop of the Catholic Church, crucified by Roman Emperor Nero. The structure was commissioned by Pope Julius II in 1506 and took nearly 120 years to complete. The construction saw contributions from the master artists and architects of the Renaissance era, including Michelangelo and Raphael.

More about St. Peter's Basilica history

Who Designed St. Peter's Basilica?

For a massive structure like St. Peter's Basilica that took over a century to build, the Vatican hired the best architects in Rome

Bramante: The initial plan was created by Renaissance artist Donato Bramante at the request of Pope. Bramante modeled the Basilica after the Roman Pantheon. Bramante died in 1514.

Giuliano da Sangallo: After Bramante’s death, the work went to Giuliano da Sangallo and Fra Giocondo. 

Raphael: After Giuliano da Sangallo and Fra Giocondo died in 1515, Raphael took over. 

Michelangelo: Michelangelo, who first desisted, designed the Dome and helped the structure as we see it today.

Carlo Maderno: Maderno was primarily known for his work on the nave and facade of the Basilica, after being appointed by the Pope in 1602.

Bernini: Bernini finally took over and created many iconic elements inside the Basilica including St. Peter’s Chair and the Baldacchino.

St. Peter's Basilica Architecture & Design

St. Peter’s Basilica Architecture

St. Peter's Basilica was built in Baroque style architecture.  It follows the style of the Roman Pantheon, but Michelangelo modified the final design to include the supporting piers to hold the massive dome. The core plan of Bramante was to match the Basilica to a Latin cross.

The interior was opulent with marbles, Renaissance-era sculptures as well as artefacts. After Bernini built the Baldacchino and St. Peter's chair to complete the structure, St. Peter's Chair, the Church has become a textbook symbol of the renaissance.

Early Stages of Construction

Piers

The base piers of St. Peter's Basilica were 45-meters high. To plant the piers, trenches as deep as 25 feet were dug. Designer Bramante raised the 90 piers to lock them under the coffered barrel vaults at 150 feet. For the Dome, he placed four piers to the Corinthian Capitals. Bramante was a fan of creating large spaces while fixing the piers with pilasters. It's also noted that no one in history has ever attempted a massive formation.

Basilica Floor

The floor of St. Peter's Basilica changed in design when Sangallo took over from Bramante. He has raised the entire floor proposed by Bramante by 12.5 feet. It's believed that Sangallo calculated the possibility of the Cathedral sinking in the marshy region it was built. To support the structure, he had built parallel walls in three feet thickness. He has also strengthened the piers Bramante created to accommodate the changes.

Materials

The material Bramante used in the construction of St. Peter’s Basilica was a lime-based sedimentary rock named travertine. It was very durable and had great strength. The construction team used the travertine quarried from Tivoli, a mineral-rich town near the Vatican. When Pope Julius II asked the designer to cut costs, Bramante limited the use of travertine and explored alternative options like bricks. Marble was another important ingredient. Architects have also used materials sourced from other buildings.

Dimensions

An architectural marvel, St. Peter's Basilica is 452 feet high; Its dome is the tallest in the world. The Basilica is 730 feet in length, and its interior is almost 693 feet. The entire area of the building and its surroundings is 5.7 acres. The interior is 15,160 square meters in area. The internal diameter of the dome, designed by Michelangelo, is 41.47 meters, breaking the record of Old Roman buildings from that age including the Pantheon.

The Exterior & Interior of St. Peter’s Basilica

St. Peter’s Basilica Architecture

St. Peter's Basilica Exterior

The most important attraction of St. Peter's Basilica is its long forecourt, St. Peter's Square, inspired by Greek style. The exterior of the Basilica is decorated with sculptures. On the facade, ornate Corinthian Columns bearing the statues of Jesus' apostles are visible. There are two giant statues of St. Peter and St. Paul placed on the entrance as well.

St. Peter’s Basilica Architecture

St. Peter's Basilica Interior

As St. Peter's Basilica is one of the most beautiful examples of Renaissance architecture, it sure has a list of invaluable treasures inside, in terms of design elements as well as artefacts. The list of works includes Michelangelo's Pieta, Bernini's bronze Baldacchino, and St. Peter's chair. A neoclassical sculpture of Pope Pius VI is also considered a masterpiece, among other Papal monuments.

Main Highlights of St. Peter's Basilica Architecture

St. Peter’s Basilica is noted for its unique architectural style. It's home to a treasure-trove of artefacts and Baroque-style construction from the Renaissance age. Everything, including the Dome of the Basilica was new to the architecture style prevalent at that time.

St. Peter’s Basilica Architecture

Facade

The facade of St. Peter's Basilica is 118.6 meters wide and 48 meters high. It's standing on its own, without the support of the building because it was built independently by architect Carlo Maderno. The construction of the facade had begun in 1607, but the first stone was laid only in 1608. In 1612 the entire structure was completed.

St. Peter’s Basilica Architecture

Dome

The Dome of St. Peter's Basilica is a quintessential part of the Vatican skyline. Italian master Michelangelo designed the Dome, altering the design of Bramante, who was the first architect of the Basilica. The massive structure is supported by four piers, each of them 60-feet thick. St. Peter's Basilica Dome is 136.57 in total height and has an inner diameter of 136 feet.

More about St. Peter's Basilica Dome
St. Peter’s Basilica Architecture

Atrium

The Atrium of St. Peter's Basilica was created by the great Italian architect Carlo Maderno. The structure stretches 71 meters in length, 12.89 meters in width, and stands tall at 19 meters. Bearing the traces of the Old St. Peter's Basilica, the construction of the Atrium began in 1608 and finished in 1612. The portico is adorned with ancient medallions. And one of the five monumental doors of the Basilica, the Holy Door, only opens once every 25 years.

St. Peter’s Basilica Architecture

Entrances

There are five entrances in the Atrium to enter the Basilica. All the doors are made in Bronze. Of all, the Holy Door is considered very sacred by the pilgrims. It's smaller, but the symbolism lies deep. The believers stop before the door, praying. The names of the other doors are the Door of death, the Door of Good and Evil, Central Door, and the Door of Sacraments.

More about St. Peter's Entrances
St. Peter’s Basilica Architecture

Altars

There are over 25 Altars inside St. Peter’s Basilica but the most sacred altar, without any doubt, is the Papal Altar built over the tomb of St. Peter, the crucified first Bishop of the Catholic Church. It's also known as the High Altar considering its importance. The entire idea of St. Peter’s Basilica, in fact, was conceived over commemorating the sacrifice of St. Peter.

More about the Papal Altar
St. Peter’s Basilica Architecture

Chapels

St. Peter’s Basilica has eleven chapels in its nave. These include chapels surrounding the Dome as well. All the chapels are decorated with stuccos and precious artworks by master artists. The most famous chapel among all perhaps is the Chapel of the Pieta. Sculpted by Michelangelo at age 24, the sculpture of Pieta shows Virgin Mary grieving while holding her arms to the dead body of Jesus Christ.

St. Peter’s Basilica Architecture

Nave

The design of the naves of St. Peter's Basilica is a testament to its architectural superiority. The walls of the central nave have inscriptions praising St. Peter and the Christian faith in general. The central nave also has two large holy water Stoups designed by a group of Italian Renaissance architects. Another stunning attraction is the 39 statues of religious figures designed within the pilasters.

St. Peter’s Basilica Architecture

Sculptures

St. Peter's Basilica is home to the artworks of some of the greatest artists from the Renaissance period. Great masters like Raphael, Bernini, and Michelangelo have contributed to the treasure trove of collections inside the Basilica. While Bernini immortalized the Baldacchino, Michelangelo's splendid works, such as the Pieta, adorn one of the chapels of Basilica.

More about St. Peter's Basilica Sculptures
St. Peter’s Basilica Architecture

Tombs

St. Peter's Basilica is built over the Tomb of St. Peter. The design of the Basilica allows the High Altar to come directly above the tomb of the first Bishop. The Church is also a resting place for many revered Popes from the past. The Papal tombs under the Basilica where Popes - past, present, and future - would be buried. You can also find another burial site within the church from ancient Rome called the Vatican Necropolis. This area was discovered through modern excavations and is now open to the public.

More about St. Peter's Tomb

St. Peter's Square

Diving into the architecture of the Basilica would be incomplete without the mention of St. Peter's Square.

St. Peter’s Basilica Architecture

Gian Lorenzo Bernini created the massive elliptical piazza in front of St. Peter's Basilica between 1657 -1667. The grand public square was designed in mind to accommodate the masses turning up for the Feast of Corpus Christi. One of the biggest public venues in the world, St. Peter’s Square is 320 meters in length and 240 meters in width.

The large expanse can hold as many as 3,00,000 people. It’s most stunning feature is its endless colonnades, forming the borders of the square. You will also find statues of 140 Saints atop the colonnades and 2 identical fountains at the center of the square.

More about St. Peter's Square

St. Peter’s Basilica | Still an Architectural Wonder Today

A marvelous architectural triumph, St. Peter's Basilica is a unique structure in its own right. There are very few buildings that carry the baroque style architecture from the renaissance era. With a history dating back centuries, and the signature of artists like Michelangelo still on the Basilica is a treasure-trove for both believers and enthusiasts.

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Frequently Asked Questions About St. Peter's Basilica Architecture

Q. What is St. Peter’s Basilica?

A. St. Peter's Basilica in the Vatican is a massive Renaissance-era church built to commemorate St. Peter, one of the twelve apostles of Jesus Christ.

Q. When was St. Peter’s Basilica built?

A. The work of the current Basilica was completed in 1626, nearly 120 years after crucifixion of St. Peter.

Q. What is the St. Peter’s Basilica architectural style?

A. St. Peter's Basilica architecture follows the famed Renaissance-era and Baroque style.

Q. Who designed St. Peter’s Basilica?

A. The first main architect of St. Peter's Basilica was an Italian Architect named Donato Bramante. But throughout its construction, the building saw at least five artists contribute to its design.

Q. What are the dimensions of St. Peter’s Basilica?

A. St. Peter’s Basilica is sprawling across 2.3 hectares. It's 220 meters in length, 150 meters in width, and 136 meters high.

Q. What’s inside St. Peter’s Basilica?

A. The main attraction inside the Basilica is the Dome built over the Tomb of St. Peter. It is also famous for its Papal Altar, artworks, tombs, & much more.

Q. Why is the St. Peter’s Basilica architecture famous?

A. Throughout its construction, St. Peter's Basilica adopted the best of Baroque-style architecture and flourished during the Renaissance. World-famous artists such as Michelangelo and Raphael have contributed to the structure.

Q. What is on the exterior of St. Peter’s Basilica?

A. St. Peter’s Basilica has a beautiful facade decorated with giant sculptures from the Renaissance era. The beauty of its exterior also includes the large plaza known as St. Peter's Square.

Q. What is part of the interior of St. Peter’s Basilica?

A. The major attraction of the interior of St. Peter's Basilica is the ornate designs & sculptures. It also has the sacred Papal Altar, Baldacchino, and invaluable sculptures such as the Pieta.

Q. Is St. Peter’s Square part of the St. Peter’s Basilica architecture?

A. Yes. St. Peter's Square is an extension of the Basilica, almost welcoming its visitors with open arms.

Q. What sculptures are part of the St. Peter’s Basilica architecture?

A. The architecture of the Basilica includes a variety of sculptures created by various artists. The Monument to Pope Alexander VII, The Pieta, and St. Andrew Sacristy are among the main attractions.

Q. What tombs are part of the St. Peter’s Basilica architecture?

A. The Tomb of St. Peter is the literal pillar on which St. Peter's Basilica is built, aside from which, Popes from yesteryears were laid to rest.