Holy See
Although the Holy See is sometimes metonymically referred to as the "Vatican", the Vatican City State was distinctively established with the Lateran Treaty (1929) between the Holy See and Italy to ensure the temporal, diplomatic, and spiritual independence of the Papacy. As such, ambassadors are officially accredited to the Holy See and not the Vatican City State. Conversely, Papal nuncios to states and international organisations are recognised as representing the Holy See and the integrity of the Catholic Church along with its 1.3 billion members, not the Vatican City State, as prescribed also in the Canon law of the Catholic Church (1983). The "Holy See" thus refers to the See of Rome viewed as the central government of the Catholic Church. The Catholic Church, in turn, is the largest non-government provider of education and health care in the world, while the diplomatic status of the Holy See facilitates the access of its vast international network of charities.
Vatican Necropolis
According to tradition, the Apostle Peter was martyred in the year 64 or 67 during the reign of Emperor Nero. Peter is said to be buried in the necropolis because of its proximity to the Circus of Nero where he was martyred. After the Edict of Milan the Emperor Constantine began construction of the first St. Peter's Church, also known as Old St. Peter's Basilica. At this time, the Roman necropolis was still in use. This is known because a coin was found inside an urn dating from 318 AD. During this time, the necropolis was protected by law and was untouchable. However, Emperor Constantine I decided to build a basilica, which would be located just above the supposed grave of the Apostle Peter. To obtain the necessary amount of flat area for the planned construction, Emperor Constantine I excavated part of the necropolis of the Vatican hill, which can be seen in the figure. This caused the necropolis to be filled with soil and building debris, with the exception of St. Peter's tomb, which was preserved.