Apostolic succession is the tracing of a direct line of apostolic ordination, orthodox doctrine, and full communion from the Apostles to the current episcopacy of the Orthodox Church. All three elements are constitutive of apostolic succession. It is through apostolic succession that the Church of Christ, which is His Body on earth, is the spiritual successor to the original body of believers in Christ that was composed of the Apostles. This succession manifests itself through the unbroken succession of its Bishops back to the Apostles.
Apostolic succession is an indispensable factor in preserving unity in the Church. Those in that succession are accountable to it, and are responsible to ensure that all teaching and practice in the Church is in keeping with her apostolic foundations. Mere personal conviction that one's teaching is correct can never be considered adequate proof of accuracy, nor does it establish validity of Holy Orders and, therefore, the Sacraments. Today, critics of apostolic succession are those who stand outside that historic succession and seek an identity with the early Church only. The burgeoning number of denominations in the world can be accounted for in large measure because of a rejection of apostolic succession.
Our Apostolic lines of unbroken succession include : The Ancient British (Celtic) Church, The Coptic Orthodox Church, The Chaldean Catholic Church, The Syrian-Orthodox Patriarchate of Antioch, The Russian Orthodox Church, The Melkite-Greek Patriarchate of Antioch and all East, The Old Catholic Church, Duarte Costa Succession: Roman Catholic.