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.
Holy See
The apostolic see of Rome was established in the 1st century by Saint Peter ("Prince of the Apostles") and Saint Paul, then the capital of the Roman Empire, according to Catholic tradition. The legal status of the Catholic Church and its property was recognised by the Edict of Milan in 313 by Roman Emperor Constantine the Great, and it became the state church of the Roman Empire by the Edict of Thessalonica in 380.