The Papal Basilica of Saint Peter in the Vatican, or simply Saint Peter's Basilica, is a church of the Italian High Renaissance located in Vatican City, an independent microstate enclaved within the city of Rome, Italy. It was initially planned in the 15th century by Pope Nicholas V and then Pope Julius II to replace the ageing Old St. Peter's Basilica, which was built in the fourth century by Roman emperor Constantine the Great. Construction of the present basilica began on 18 April 1506 and was completed on 18 November 1626.

Renaissance architecture is the European architecture of the period between the early 15th and early 16th centuries in different regions, demonstrating a conscious revival and development of certain elements of ancient Greek and Roman thought and material culture. Stylistically, Renaissance architecture followed Gothic architecture and was succeeded by Baroque architecture and neoclassical architecture. Developed first in Florence, with Filippo Brunelleschi as one of its innovators, the Renaissance style quickly spread to other Italian cities. The style was carried to other parts of Europe at different dates and with varying degrees of impact.