Saint Peter's Basilica (1590). The Papal Basilica of St. Peter in the Vatican, or simply St. Peter's Basilica, 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 the largest church 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 asthe 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. Saint Peter's tomb is supposedly 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, and there has been a church on this site since the time of the Roman emperor Constantine the Great. Construction of the present basilica, which would replace Old St. Peter's Basilica from the 4th century AD, began on 18 April 1506 and was completed on 18 November 1626. 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, drawing audiences of 15,000 to over 80,000 people, either within the basilica or the adjoining St. Peter's Square. 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 one of the four churches in the world that hold the rank of major basilica, all four of which are in Rome. Contrary to popular misconception, it is not a cathedral because it is not the seat of a bishop; the cathedra of the pope as Bishop of Rome is in the Archbasilica of St. John Lateran. 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 trapezoid. The facade 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 metres statues of the 1st-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. 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, only opened during jubilees. The interior is of vast dimensions when compared with 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.