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.
Languages of Vatican City
What became Vatican City was from 1870 to 1929 part of the Kingdom of Italy, whose official language also was Italian, and before 1870 it was part of the Papal States, in which standard Italian (based on Tuscan) and various Italian dialects, such as Emiliano-Romagnolo, were spoken, but which for the first centuries of its existence used Latin for all official purposes. Earlier still, it was part of the Roman Empire. In the earliest historical records the term "Vatican" was used to refer to a marshy area, larger than the Vatican City State, on the right bank of the Tiber River, between the Milvio Bridge and the present Sixtus Bridge. During the monarchy and the republican age, the area was known as "Ager Vaticanus". From the 2nd century A.D., the toponym "Vaticanum" was applied to an area corresponding roughly to the present Vatican City State.