Although the Holy See is sometimes metonymically referred to as the "Vatican", the Vatican City State was distinctively established with the Lateran Treaty of 1929, between the Holy See and Italy, to ensure the temporal, diplomatic, and spiritual independence of the papacy. As such, papal nuncios, who are papal diplomats to states and international organizations, are recognized as representing the Holy See not the Vatican City State, as prescribed in the Canon law of the Catholic Church; and therefore the integrity of the Catholic Church along with its 1.3 billion members. The Holy See is thus 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. The diplomatic status of the Holy See facilitates the access of its vast international network of charities.
The word "see" comes from the Latin word sedes, meaning 'seat', which refers to the episcopal throne (cathedra). The term "Apostolic See" can refer to any see founded by one of the Twelve Apostles, but, when used with the definite article, it is used in the Catholic Church to refer specifically to the see of the Bishop of Rome, whom that Church sees as successor of Saint Peter. While Saint Peter's Basilica in Vatican City is perhaps the church most associated with the papacy, the actual cathedral of the Holy See is the Archbasilica of Saint John Lateran in the city of Rome.[note 1]
Every see is considered holy. In Greek, the adjective "holy" or "sacred" (ἱερά transliterated as hiera) is constantly applied to all such sees as a matter of course. In the West, the adjective is not commonly added, but it does form part of an official title of two sees: besides the Holy See, the Bishopric of Mainz (the former Archbishopric of Mainz, which was also of electoral and primatial rank) bears the title of "the Holy See of Mainz" (Latin: Sancta Sedes Moguntina).