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 and Eastern Europe (1846–1958)
The relations with Russia changed drastically for a second reason. The Baltic states and Poland gained their independence from Russia after World War I, thus enabling a relatively free church life in those former Russian countries. Estonia was the first country to look for Vatican ties. On 11 April 1919, Secretary of State Pietro Gasparri informed the Estonian authorities that the Vatican would agree to have diplomatic relations. A concordat was agreed upon in principle a year later, in June 1920. Because of the small Catholic population in predominantly Protestant Estonia, the handful of Catholic priests there continued to be administered from Latvia until 1924. Development of an independent Catholic hierarchy for Estonia began late in that year with the formation of the Apostolic Administration of Estonia in November.