The Vatican’s history as the Catholic Church’s seat began with constructing the basilica in the 4th century A.D., over St. Peter’s grave in Rome. The area evolved into a popular pilgrimage site and commercial district. However, it was abandoned in 1309, following the move of the papal court to France. Following the Church’s return in 1377, famous landmarks such as the Sistine Chapel, new St. Peter’s Basilica, and the Apostolic Palace were raised within the city borders. With the 1929s Lateran Pacts signing, Vatican City was established in its current form as a sovereign nation. .

The area off the west shore of the Tiber River that comprises the Vatican was once a wetland region known as Ager Vaticanus. In the early years of the Roman Empire, it became an authorized region populated by expensive villas and a circus built in Emperor Caligula’s mother’s gardens. After the majority of Rome was destroyed in a fire in A.D. 64, Emperor Nero executed St. Peter. Other Christian victims were conducted together with St. Peter at the base of Vatican Hill. They were buried there in a necropolis.

After embracing Christianity in 313, Emperor Constantine I began the construction of a basilica in 324 that was placed over St. Peter’s tomb. St. Peter’s Basilica became a religious center for Christian wanderers, leading to a housing development for clergymen and forming a marketplace that became the thriving commercial area of Borgo.