Organization of the Eastern Orthodox Church

[1][2][3][4] Each constituent church is self-governing;[2] its highest-ranking bishop called the primate (a patriarch, a metropolitan or an archbishop) reports to no higher authority.

[6] The Eastern Orthodox Church is decentralised, having no central authority, earthly head or a single bishop in a leadership role.

Thus, the Eastern Orthodox use a synodical system canonically, which is significantly different from the hierarchical organisation of the Catholic Church that follows the doctrine of papal supremacy.

[6] References to the Ecumenical Patriarch of Constantinople as a sole authoritative leader are an erroneous interpretation of his title “first among equals".

[9] The Ecumenical Patriarch's unique role is sometimes referred to as being the "spiritual leader" of the Eastern Orthodox Church, although even this is disputed.

The four ancient Eastern Orthodox Patriarchates, along with the See of Rome, formed the historical Pentarchy, and remained in communion with each other after the East-West Schism in 1054.

The concept of the Pentarchy and the title of "Patriarch" itself, as opposed to Archbishop or Exarch, is attributed to St Justinian in AD 531.

[25] These groups refrain from concelebration of the Divine Liturgy with the mainstream Eastern Orthodox, while maintaining that they remain fully within the canonical boundaries of the Church: i.e., professing Eastern Orthodox belief, retaining legitimate apostolic succession, and existing in communities with historical continuity.