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
Mother See of Holy Etchmiadzin Mother See of Holy Etchmiadzin Mother See of Holy Etchmiadzin (, "Mayr At'oř Surb Ēĵmiatsin"), is the governing body of the Armenian Apostolic Church. It is headquartered around Etchmiadzin Cathedral in Vagharshapat (Etchmiadzin), Armenia and is the seat of the Catholicos of All Armenians, the head of the church. The organizational structure of the Mother See of Holy Etchmiadzin is composed of spiritual and administrative bodies representing the authority of the Armenian Church, as follows: The Supreme Spiritual Council ( "Geraguyn Hokevor Khorhurt") is headed by the Catholicos of All Armenians. It is the highest executive body of the Armenian