The Papal Basilica of St. Peter in the Vatican (Basilica Papale di San Pietro in Vaticano), or simply St. Peter’s Basilica (Basilica Sancti Petri), is an Italian Renaissance church in Vatican City, the papal enclave within the city of Rome.Designed principally by Donato Bramante, Michelangelo, Carlo Maderno and Gian Lorenzo Bernini, St. Peter’s is the most renowned work of Renaissance architecture and one of the largest churches in the world. While it is neither the mother church of the Catholic Church nor the cathedral of the Diocese of Rome, St. 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 St. Peter, one of Christ’s Apostles and also the first Pope; supposedly, St. Peter’s tomb is directly below the high altar of the Basilica. For this reason, many Popes have been interred at St. Peter’s since the Early Christian period. There has been a church on this site since the time of the Roman Emperor Constantine the Great. Construction of the present basilica, replacing the Old St. Peter’s Basilica of the 4th century AD, began on 18 April 1506 and was completed on 18 November 1626.