The Kingdom of Armenia was the first state to adopt Christianity as its official religion in AD 301, when St. Gregory the Illuminator, or St. Gregory the Enlightener, converted King Tiridates III and members of his court into the Christian religion. The Armenian Apostolic Church is the world’s oldest national church. The Church is part of Oriental Orthodoxy, and the Armenians are proud that the origins of their Mother Church are traced to the missions of Apostles Bartholomew and Thaddaeus in the 1st century, when it became an early center of Christianity. This is why the Armenian Church is named “Apostolic”, that is to say, of the Holy Apostles of Christ.
Saint Gregory the Illuminator is the patron saint and first official head (Catholicos) of the Armenian Apostolic Church. He is a much respected religious figure in Armenia, and is declared to be “the second Enlightener” after the historical missions of St. Bartholomew and St. Thaddaeus.
The Armenian Apostolic Church presently has two Catholicoi (in the church hierarchy the position of the Catholicos is higher than that of the Patriarch) and two Patriarchs: The Supreme Patriarch and Catholicos of All Armenians, The Catholicos of the Great House of Cilicia, The Armenian Patriarch of Jerusalem, whose Patriarchate has jurisdiction over all of the Holy Lands and the Diocese of Jordan, and The Armenian Patriarch of Constantinople and all of Turkey, whose Patriarchate has jurisdiction in the modern day Republic of Turkey.
After its establishment the Armenian Apostolic Church participated in the larger church world. Its Catholicoi were represented at the First Council of Nicea (325) and the First Council of Constantinople (381). Although unable to attend the Council of Ephesus (431), the Catholicos Isaac Parthiev sent a message agreeing with its decisions. However, the Church has not adopted the decisions of the Council of Chalcedon (451). Because of this, the Armenian Apostolic Church has been referred by some theologians to as monophysite. However, it argues that the identification as “Monophysitism” is an incorrect description of its position. It considers Monophysitism, as taught by Eutyches and condemned at Chalcedon, a heresy and only disagrees with the formula defined by the Council of Chalcedon.
The status of the Armenian Apostolic Church within the Republic of Armenia is defined in the country’s constitution. A 2005 amendment to the constitution granted the Church an “exclusive mission” within Armenia’s spiritual and cultural life.
The Armenian Apostolic Church should not be confused with the Armenian Catholic Church whose Patriarch-Catholicos (of the Armenian Catholic Rite) is Nerses Bedros XIX, which is an Eastern Catholic church in communion with the Holy See in Rome.