High Quality Content by WIKIPEDIA articles! The Papal Basilica of Saint Peter (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 the Vatican City. Saint Peter`s Basilica has the largest interior of any Christian church in the world. While it is neither the official mother church of the Roman Catholic Church nor the cathedral of the Pope as Bishop of Rome, Saint Peter`s is regarded as one of the holiest Catholic sites. It has been described as "holding a unique position in the Christian world" and as "the greatest of all churches of Christendom".