Holy See of the East the Church of the East after the Coonan Cross Oath and joined the Church of Antioch also claims the title of the Holy See of the East, since St. Thomas is also the founder of this churches. The Malankara Orthodox Syrian Church which evolved out of the Malankara Church as a part of the Oriental Orthodox Churches claims the title of the Catholicos of the East and the Holy Apostolic See of St. Thomas. The Malankara Syrian Catholic Church which evolved from the Malankara Church as a part of the Eastern Catholic Church in full communion with the Holy See
Holy See former Secretary for Relations with States, said that the Vatican City is a "minuscule support-state that guarantees the spiritual freedom of the Pope with the minimum territory". The Holy See, not the Vatican City, maintains diplomatic relations with states. Foreign embassies are accredited to the Holy See, not to the Vatican City, and it is the Holy See that establishes treaties and concordats with other sovereign entities. When necessary, the Holy See will enter a treaty on behalf of the Vatican City. Under the terms of the Lateran Treaty, the Holy See has extraterritorial authority over various sites in Rome