By tradition the apostle Peter was buried in a cemetery near Nero’s circus where he had been martyred. Emperor Constantine built the original Basilica of Saint Peter on that spot around the year 320. The building was comparable with the current one in size and consisted of five naves preceded by a large atrium with a quadriportico and a cantharos for ablutions. 

The long process that would lead in the span of about two hundred years and with the contribution of a great many artists to the complete rebuilding of the ancient Constantinian basilica started under the papacy of Nicholas the Fifth Parentucelli (1447-1455). The turning point was under Julian the Second Della Rovere (1503-1513), who in 1505 decided to rebuild the temple thoroughly, commissioning the works to Donato Bramante. 

Bramante started a grand palace with a Greek cross plan and dome, which however was left unfinished, due to the death of both the pope that commissioned it and of Bramante (1514). Then  followed a period of uncertainties and second thoughts during which the works were supervised successively by Rafael, Baldassarre Peruzzi, and Antonio da San Gallo. San Gallo in particular diverged from the original design proposing a more traditional Latin cross plan. In 1547 Paul the Third Farnese appointed Michelangelo to continue the works. 

The old master was more than seventy years old. He decided to go back to Bramante’s plan, but projected it upwards with the powerful and yet slender dome, made by Michelangelo up to the tambour and completed with a few changes by Giacomo della Porta between 1588 and 1590. Under the papacy of Paul the Fifth Borghese (1605-1621) Carlo Maderno was appointed to complete the works. He added three small side chapels – thus reintroducing the Latin Cross plan - and built the controversial facade, completed in 1614. 

In 1626 the basilica was finally consecrated by pope Urbanthe Eighth Barberini (1623-1644). Starting from 1629 the supervision of the works was assigned to Gian Lorenzo Bernini, who made most of the decorations and definitively arranged the square in front of the church building the renowned colonnade between 1656 and 1665. The imposing facade is 15 meters long and preceded by the three story stairway designed by Bernini. It presents pilasters and Corinthian columns and is surmounted by an attic crowned by thirteen colossal statues. 

The Loggia of Blessings is placed at the centre. It is here that the pope blesses the faithful on the most solemn occasions and the election of a new pope is announced to the world. Constantine’s equestrian statue by Bernini can be seen from the wide atrium designed by Maderno through a glass door. 

The central of the five entrance doors is remarkable. Its wings are a fifteenth century work by Filarete (they were already in the ancient basilica). The Porta Santa, whose opening gives the official start to the Holy Year, is the last door on the right. The size of the interior is indeed large and presents a central nave with two side aisles. 

The Rota Porphyretica, a porphyry disk (that was previously next to the altar of the ancient basilica) on which Charlemagne kneeled to receive the imperial crown from Leo the Third on Christmas Eve in the year 800 is only a few yards away from the entrance on the floor of the central nave. Proceeding towards the altar, the lengths of the largest churches in the world are indicated on the floor in bronze letters. 

On the last right pillar a famous bronze statue representing Saint Peter seated and benedictive – for a long time considered to be of the fifth century, but now attributed with certainty to the thirteenth century and perhaps even to Arnolfo di Cambio – leads to the dome, whose bright interior was decorated with mosaics by Cavalier d’Arpino in 1605. 

The spiral columns of the enormous bronze baldachin designed by Gian Lorenzo Bernini between 1624 ed il 1633 in collaboration with other artists including Francesco Borromini stand out under the dome supported by four colossal pillars by Bramante with statues of saints decorating their bases (of particular interest the San Longino by Bernini under the first right pillar). 

The papal altar is under the baldachin and overlooks the confession designed by Maderno aligned with the underlying tomb of Saint Peter. Bernini also designed the spectacular Saint Peter’s Chair at the centre of the apse, flanked by the funerary monuments of both Urban the Eighth, also designed by Bernini and of Paul the Third, exceptional work by Guglielmo della Porta. 

The Pietà, the famous marble group signed by Michelangelo, who sculptured it when he was only twenty-three (1498-99) for a French cardinal, is displayed in the first chapel in the right nave behind a protective glass. Proceeding along the right nave there are other chapels all with decorations and works of exceptional level (in the third chapel, called “of the Sacrament”, there are wrought bars by Borromini and a ciborium by Bernini inspired to San Pietro in Montorio). 

In the right transept there is a monument of Clement the Thirteenth, one of the most famous works by Antonio Canova (1784-92). The tomb of Innocent the Eighth by Pollaiolo (1498), the most ancient funeral monument present in the basilica, and the funerary stele known as the monument to Stuart by Antonio Canova are in the left nave.