St. Peter's Basilica, or more precisely St. Peter's Basilica in the Vatican (in Latin: Sancti Petri and in Italian: San Pietro in Vaticano) is the most important religious edifice of Catholicism. It is located in the Vatican, on the right bank of the Tiber, and its façade opens on St. Peter's Square.
It was built where the first pilgrims came to worship Saint-Pierre, under the will of the Emperor Constantine, at the site of the circus of Nero.
Inscribed on the UNESCO World Heritage List, St. Peter's Basilica is considered the greatest architectural design of its time and remains one of the most visited monuments in the world. Its construction, on the site of the ancient basilica built under the Emperor Constantine, begins on April 18, 1506 and is completed in 1626. Its most important architects are Bramante, Michelangelo and Bernini.
Saint Peter's Basilica is an important place of pilgrimage that brings together at least 150,000 Catholics every Sunday during the pontifical Angelus. It is not the cathedral of the diocese of Rome, since the bishop of the city sits in St. John Lateran, but it is the church of the pope and the pontifical state. It is also one of the two parish churches of the Vatican City (the other being the Church of Sant'Anna dei Palafrenieri). Although the New Testament does not mention the presence of the Apostle Peter, the first head of the Christian Church in Rome or his martyrdom in that city, the Catholic tradition indicates that the Tomb of St. Peter is located under the high altar, In the center of the church, under the baroque canopy.
St. Peter's Basilica is the second of the four major basilicas of Rome, after St. John Lateran, before St. Mary Major and St. Paul Outside the Walls.
With an area of 2.3 ha and a capacity of more than 20,000 people, it is the largest Catholic church. It is also one of the holiest places of Christianity, since it houses the tomb of St. Peter, who according to Catholic tradition was the first bishop of Antioch and Rome, and therefore the first pope.
At the beginning of the Roman Empire, shortly before the birth of Christ, the site was occupied by some villas, built around imperial gardens which were the property of Agrippina the Elder. His son, Caligula (AD 37-41), built a private circus, the Circus Vaticanus or Circus of Caligula and Nero, of which the present obelisk of the Vatican constitutes one of the only vestiges.
It was in this circus, as well as in the adjoining gardens, that the martyrdom of many Christians of Rome in the time of Nero took place (54-68). An immemorial tradition places the martyrdom of the Apostle Peter inside the circus - inter duas metas ( "between two bounds") of the spina, whose center was occupied by the Obelisk of the Vatican. According to the tradition transmitted by apocryphal works (such as the Acts of Peter), Peter was crucified about 65, head down from humility, for he did not consider himself worthy to die like Christ. According to another version, it may be an additional cruelty voluntarily inflicted by the Romans.