St. Peter's, a basilica in Vatican City. (“Basilica” is a title of honor conferred on certain historic or privileged churches by the Roman Catholic Church.) St. Peter's is the largest and most noted Christian church in the world. Its site is said to be that of Nero's Circus, where many early Christians were put to death. St. Peter's was built between 1506 and 1626 to replace the fourth-century basilica erected by Constantine. A masterpiece of the Italian High Renaissance, St. Peter's is the work of a number of 16th-century architects. The form of the present church is due mainly to three men—Michelangelo, Carlo Maderna, and Giovanni Lorenzo Bernini.
The imposing entrance square, the Piazza di San Pietro, is partly encircled by two large colonnades. In the center an 82-foot (25-m) obelisk stands between two fountains. A triple flight of steps leads to the eastern facade, 375 feet (114 m) wide and 167 feet (51 m) high. Although the dome with its lantern and cross rises 452 feet (138 m), the facade cuts off its view from the piazza.
There are five entrances to the church. The central bronze doors were in the original St. Peter's. The Holy Door, on the far right, is opened by the pope only in Holy Years. On the extreme left are the Doors of Death, depicting such scenes as the Crucifixion, the stoning of Saint Stephen, and Cain killing Abel. These bronze doors, designed by the 20th-century sculptor Giacomo Manzù and completed in 1964, replaced oak doors that had been considered temporary for 500 years.
The church is in the form of a Latin cross. It is 613 feet (187 m) long and, at the transepts, 450 feet (137 m) wide. At the beginning of the nave a round slab of porphyry marks the spot where the Holy Roman emperors were crowned. The dome, 137 1/2 feet (42 m) in diameter, rises 335 feet (102 m) from the floor. It is supported by four massive piers, each 240 feet (73 m) in circumference. A frieze below the drum of the dome bears a Latin inscription for “Thou art Peter, and on this rock I will build my church.”
Beneath the dome Bernini's bronze baldacchino, or canopy, rises about 100 feet (30 m) over the high altar. Behind the altar, in the western apse, is St. Peter's Chair, also by Bernini. In front of the altar is the confessione, a sunken semicircular area. Stairs in it lead to the chamber below, containing the sarcophagus long revered as that of Saint Peter. Nearby is a bronze statue of Saint Peter seated. The toes of its extended foot are worn and shiny from the kisses of the faithful.
An earlier basilica was built here by Constantine in the fourth century. Over the years the building deteriorated and in the 15th century Pope Nicholas V ordered St. Peter's repaired. His death in 1455 halted the work. About 50 years later Pope Julius II decided to build a new basilica. Donate Bramante won the competition to design it. Bramante planned a Greek-cross church, roofed by a vast central dome. The foundation was laid in 1506.
After Raphael's death in 1520, a number of architects continued to build and redesign St. Peter's, alternating between Latin-cross and Greek-cross plans. When Michelangelo was appointed architect in 1546, he returned to Bramante's plan but enlarged the dome and redesigned the chapels and apses. The dome was completed from his plans after his death in 1564.
About 1605 Pope Paul V ordered Carlo Maderna to extend the nave to form a Latin cross and to design a new facade. The church was dedicated in 1626. Bernini, appointed architect in 1629, designed the colonnaded entrance piazza and many of the interior monuments.
Excavations beneath St. Peter's were begun in the 1940's. In 1950 Pope Pius XII announced that archeologists had identified the tomb of Saint Peter. In 1968 Pope Paul VI announced that bones discovered in the 1953 excavations had been identified as those of Saint Peter. Many scholars, however, believe that there is insufficient evidence for firm identification of the tomb and remains as those of Saint Peter.