Catholicos

The catholicos is the title of the head of certain Eastern churches that developed beyond the frontiers of the Roman Empire, notably the Armenian, Georgian and Assyrian churches.

Head of a national church

The title arose for the leaders of churches that lay outside the Roman Empire, in Armenia, Georgia and the Persian lands, where the ordinary structures of the imperial church did not reach, and it came to denote the supreme head of such a church, equivalent in standing to a patriarch, presiding over its bishops and governing its affairs, so the catholicos is the summit of the hierarchy in the churches that bear the title. The office is a rank built upon the episcopate, as with the patriarch and metropolitan.

The churches of the catholicos

The Armenian Apostolic Church is headed by a catholicos, and the title is likewise borne by the heads of the Georgian and the Assyrian Church of the East, ancient churches that took shape beyond the imperial frontier and developed their own independent structures, so the office marks the leadership of these distinct national and regional traditions. In some cases a church has more than one catholicos presiding over different sees. Entry is by election within the church concerned. The catholicos thus represents the supreme head of certain of the oldest Eastern churches, those that grew up outside the Roman world, and the title, equivalent to that of patriarch, marks their independent origin and their self-governing character as ancient churches with their own line of supreme authority.

The Armenian church traces its catholicosate to Gregory the Illuminator, traditionally credited with converting King Tiridates III and establishing Christianity as the state religion of Armenia at the start of the fourth century, an adoption tradition places before the Roman Empire's own toleration and later establishment of Christianity under Constantine and his successors, making Armenia, on the traditional dating, an early and possibly the first state to adopt Christianity officially, though the precise year is debated among historians working from limited and not fully consistent early sources.

The Armenian church subsequently rejected the christological definition of the Council of Chalcedon in 451, placing it, along with the Georgian church for several further centuries and the Assyrian Church of the East on separate grounds again, outside full communion with both Rome and Constantinople from an early date, so the catholicosate of these churches developed in genuine doctrinal as well as geographic independence from the imperial church, a separation that has persisted for over fifteen centuries and that modern ecumenical dialogue between these churches and the Chalcedonian traditions has only partially addressed.