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It is supposed that this originally uninhabited part of Rome (the ager vaticanus) had always been considered sacred, even before the arrival of Christianity. In 326 the first church, Constantine's basilica, was built over the supposed site of the tomb of Saint Peter, and from then on the area started to become more populated.
Popes in their secular role gradually extended their control over neighbouring regions and, through the Papal States, ruled a large portion of the Italian peninsula for more than a thousand years until the mid 19th century, when most of the territory of the Papal States was seized by the newly united Kingdom of Italy.
In 1870, the Pope's holdings were further circumscribed when Rome itself was annexed. Disputes between a series of "prisoner" popes and Italy were resolved on February 11, 1929 by three Lateran treaties, which established, under Mussolini, the independent state of the Vatican City and granted Roman Catholicism special status in Italy. The Cathedra (official seat) of the Bishop of Rome, the Pope, is in the apse of St. John Lateran, which although it sits on Italian territory enjoys extraterritoriality (immunity from Italian law) as a result of the 1929 treaty. The Lateran is on one of the 7 hills of Rome (the Caelian). In 1984, a new concordat between the Holy See and Italy modified certain provisions of the earlier treaty, including the primacy of Roman Catholicism as the Italian state religion.
Popes in their secular role gradually extended their control over neighbouring regions and, through the Papal States, ruled a large portion of the Italian peninsula for more than a thousand years until the mid 19th century, when most of the territory of the Papal States was seized by the newly united Kingdom of Italy.
In 1870, the Pope's holdings were further circumscribed when Rome itself was annexed. Disputes between a series of "prisoner" popes and Italy were resolved on February 11, 1929 by three Lateran treaties, which established, under Mussolini, the independent state of the Vatican City and granted Roman Catholicism special status in Italy. The Cathedra (official seat) of the Bishop of Rome, the Pope, is in the apse of St. John Lateran, which although it sits on Italian territory enjoys extraterritoriality (immunity from Italian law) as a result of the 1929 treaty. The Lateran is on one of the 7 hills of Rome (the Caelian). In 1984, a new concordat between the Holy See and Italy modified certain provisions of the earlier treaty, including the primacy of Roman Catholicism as the Italian state religion.