Colour lantern slide of the interior of St. Paul's in Rome.. Part of Box 197 'Sayings', Boswell Collection. The Papal Basilica of Saint Peter in the Vatican (Latin: Basilica Sancti Petri), officially known in Italian as Basilica Papale di San Pietro in Vaticano and commonly known as Saint Peter's Basilica, is a Late Renaissance church located within Vatican City. Designed principally by Donato Bramante, Michelangelo, Carlo Maderno and Gian Lorenzo Bernini, St Peter's is the most renowned work of Renaissance architecture and remains one of the largest churches in the world.