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.
Vates
In pagan Rome the vates resided on the Vatican Hill, the Hill of the Vates. The Vatican Hill takes its name from the Latin word Vaticanus, a vaticiniis ferendis, in allusion to the oracles, or Vaticinia, which were anciently delivered on the Vatican Hill. (When the papacy was returned to Rome from Avignon (France) in the 14th Century, the Vatican became the residence of the Pope, and the word Vatican came to refer to the enclave in the middle of Rome that had become the seat of the Roman Catholic Church.)