The Papal Basilica of Saint Peter in the Vatican (Italian: Basilica Papale di San Pietro in Vaticano), or simply St. Peter's Basilica (Latin: Basilica Sancti Petri; Italian: Basilica di San Pietro [baˈziːlika di sam ˈpjɛːtro]), is a church of the Italian Renaissance located in Vatican City, an independent microstate enclaved within the city of Rome, Italy. It was initially planned in the 15th century by Pope Nicholas V and then Pope Julius II to replace the ageing Old St. Peter's Basilica, which was built in the fourth century by Roman emperor Constantine the Great. Construction of the present basilica began on 18 April 1506 and was completed on 18 November 1626.
Designed principally by Donato Bramante, Michelangelo, and Carlo Maderno, with piazza and fittings by Gian Lorenzo Bernini, Saint Peter's is one of the most renowned works of Italian Renaissance architecture and is the largest church in the world by interior measure. While it is neither the mother church of the Catholic Church nor the cathedral of the Diocese of Rome (these equivalent titles being held by the Archbasilica of Saint John Lateran in Rome), Saint Peter's is regarded as one of the holiest Catholic shrines. It has been described as "holding a unique position in the Christian world", and as "the greatest of all churches of Christendom".
Catholic tradition holds that the basilica is the burial site of Saint Peter, chief among Jesus's apostles and also the first Bishop of Rome (Pope). Saint Peter's tomb is directly below the high altar of the basilica, also known as the Altar of the Confession. For this reason, many popes, cardinals and bishops have been interred at St. Peter's since the Early Christian period.
St. Peter's is famous as a place of pilgrimage and for its liturgical functions. The pope presides at a number of liturgies throughout the year both within the basilica or the adjoining St. Peter's Square; these liturgies draw audiences numbering from 15,000 to over 80,000 people. St. Peter's has many historical associations, with the early Christian Church, the Papacy, the Protestant Reformation and Catholic Counter-Reformation and numerous artists, especially Michelangelo. As a work of architecture, it is regarded as the greatest building of its age.
St. Peter's is ranked second, after the Archbasilica of Saint John Lateran, among the four churches in the world that hold the rank of major papal basilica, all four of which are in Rome, and is also one of the Seven Pilgrim Churches of Rome. Contrary to popular misconception, it is not a cathedral because it is not the seat of a bishop.
St. Peter's is a church built in the Renaissance style located in the Vatican City west of the River Tiber and near the Janiculum Hill and Hadrian's Mausoleum. Its central dome dominates the skyline of Rome. The basilica is approached via St. Peter's Square, a forecourt in two sections, both surrounded by tall colonnades. The first space is oval and the second trapezoidal. The façade of the basilica, with a giant order of columns, stretches across the end of the square and is approached by steps on which stand two 5.55-metre (18.2 ft) statues of the first-century apostles to Rome, Saints Peter and Paul.
The basilica is cruciform in shape, with an elongated nave in the Latin cross form but the early designs were for a centrally planned structure and this is still in evidence in the architecture. The central space is dominated both externally and internally by one of the largest domes in the world. Set into the niches of the dome's four gargantuan support piers are colossal statues representing the four major holy relics believed to be held in the basilica: St. Longinus with his spear, St. Helena with the True Cross, St. Veronica with her veil, and St. Andrew, whose skull was possessed by the Vatican until the 20th century. The entrance is through a narthex, or entrance hall, which stretches across the building. One of the decorated bronze doors leading from the narthex is the Holy Door, opened only during jubilees.
The interior dimensions are vast when compared to other churches. One author wrote: "Only gradually does it dawn upon us – as we watch people draw near to this or that monument, strangely they appear to shrink; they are, of course, dwarfed by the scale of everything in the building. This in its turn overwhelms us."
The nave which leads to the central dome is in three bays, with piers supporting a barrel vault, the highest of any church. The nave is framed by wide aisles which have a number of chapels off them. There are also chapels surrounding the dome. Moving around the basilica in a clockwise direction they are: The Baptistery, the Chapel of the Presentation of the Virgin, the larger Choir Chapel, the altar of the Transfiguration, the Clementine Chapel with the altar of Saint Gregory, the Sacristy Entrance, the Altar of the Lie, the left transept with altars to the Crucifixion of Saint Peter, Saint Joseph and Saint Thomas, the altar of the Sacred Heart, the Chapel of the Madonna of Column, the altar of Saint Peter and the Paralytic, the apse with the Chair of Saint Peter, the altar of Saint Peter raising Tabitha, the altar of St. Petronilla, the altar of the Archangel Michael, the altar of the Navicella, the right transept with altars of Saint Erasmus, Saints Processo and Martiniano, and Saint Wenceslas, the altar of St. Jerome, the altar of Saint Basil, the Gregorian Chapel with the altar of the Madonna of Succour, the larger Chapel of the Holy Sacrament, the Chapel of Saint Sebastian and the Chapel of the Pietà. The Monuments, in a clockwise direction, are to: Maria Clementina Sobieska, The Stuarts, Benedict XV, John XXIII, St. Pius X, Innocent VIII, Leo XI, Innocent XI, Pius VII, Pius VIII, Alexander VII, Alexander VIII, Paul III, Urban VIII, Clement X, Clement XIII, Benedict XIV, St Peter (Bronze Statue), Gregory XVI, Gregory XIV, Gregory XIII, Matilda of Canossa, Innocent XII, Pius XII, Pius XI, Christina of Sweden, and Leo XII.
At the heart of the basilica, beneath the high altar, is the Confessio or Chapel of the Confession, named in reference to the confession of faith by St. Peter, which led to his martyrdom. Two curving marble staircases lead to this underground chapel at the level of the Constantinian church and immediately above the purported burial place of Saint Peter. Pope Gregory XVI granted a "perpetual privilege" in 1836 authorizing any Catholic priest to celebrate Mass at the altar in the chapel.
The entire interior of St. Peter's is lavishly decorated with marble, reliefs, architectural sculpture and gilding. The basilica contains a large number of tombs of popes and other notable people, many of which are considered outstanding artworks. There are also a number of sculptures in niches and chapels, including Michelangelo's Pietà. The central feature is a baldachin, or canopy over the Papal Altar, designed by Gian Lorenzo Bernini. The apse culminates in a sculptural ensemble, also by Bernini, and containing the symbolic Chair of Saint Peter.
The American philosopher Ralph Waldo Emerson described St. Peter's as "an ornament of the earth ... the sublime of the beautiful."
St. Peter's Basilica is one of the papal basilicas (previously styled "patriarchal basilicas") and one of the four Major Basilicas of Rome the others (all of which are also Papal Basilicas) being the Basilicas of St. John Lateran, St. Mary Major, and St. Paul outside the Walls. The rank of major basilica confers on St. Peter's Basilica precedence before all minor basilicas worldwide. However, unlike all the other Papal Major Basilicas, it is wholly within the territory, and thus the sovereign jurisdiction, of the Vatican City State, and not that of Italy.
It is the most prominent building in the Vatican City. Its dome is a feature of the skyline of Rome and covers an area of 0.139 hectares (0.34 acres). One of the holiest sites of Christianity and Catholic Tradition, it is traditionally the burial site of its titular, St. Peter, who was the head of the twelve Apostles of Jesus and, according to tradition, the first Bishop of Antioch and later the first Bishop of Rome, rendering him the first Pope. Although the New Testament does not mention St. Peter's martyrdom in Rome, tradition, based on the writings of the Fathers of the Church, holds that his tomb is below the baldachin and the altar of the Basilica in the "Confession". For this reason, many Popes have, from the early years of the Church, been buried near Pope St. Peter in the necropolis beneath the Basilica. Construction of the current basilica, over the old Constantinian basilica, began on 18 April 1506 and finished in 1615. At length, on 18 November 1626 Pope Urban VIII solemnly dedicated the Basilica.