I understand that the Eastern Orthodox Church has some kind of leadership structure that (maybe?) can decide on doctrine for the entire church. How is this leadership structured and what can the leadership decide to do (can they declare doctrine, define disciplines, ect?)
How does the leadership structure within the Eastern Orthodox Church work?
Orthodoxy within Christianity refers to acceptance of the doctrines defined by various creeds and ecumenical councils in Antiquity, but different Churches accept different creeds and councils. Such differences of opinion have developed for numerous reasons, including language and cultural barriers. The Eastern Orthodox Church adheres to the orthodoxy portrayed mainly in the first seven ecumenical councils, while the Oriental Orthodox Churches define their orthodoxy as based on the first three ecumenical councils alone.
Eastern Orthodox Churches operate as a communion of autocephalous churches, each governed by its bishops in local synods. The church has no central doctrinal or governmental authority analogous to the Bishop of Rome (Pope), but the Ecumenical Patriarch of Constantinople is recognised by all bishops as primus inter pares ("first among equals") and regarded as the representative and spiritual leader of Eastern Orthodox Christians. One point of interest is that unlike most other Churches, the Ethiopian Church accepts 1 Enoch and the Book of Jubilees as canonical.
The Eastern Orthodox Church, also called the Orthodox Church, is the second-largest Christian Church. It operates as a communion of autocephalous churches, each governed by its bishops in local synods. The church has no central doctrinal or governmental authority analogous to the Bishop of Rome (Pope), but the Ecumenical Patriarch of Constantinople is recognised by all bishops as primus inter pares ("first among equals") and regarded as the representative and spiritual leader of Eastern Orthodox Christians.
Eastern Orthodox theology is based on holy tradition, which incorporates the dogmatic decrees of the seven ecumenical councils, the Scriptures, and the teaching of the Church Fathers. The church teaches that it is the one, holy, catholic and apostolic church established by Jesus Christ in his Great Commission, and that its bishops are the successors of Christ's apostles. It maintains that it practices the original Christian faith, as passed down by holy tradition. Its patriarchates, reminiscent of the pentarchy, and other autocephalous and autonomous churches, reflect a variety of hierarchical organisation. It recognizes seven major sacraments, of which the Eucharist is the principal one, celebrated liturgically in synaxis. The church teaches that through consecration invoked by a priest, the sacrificial bread and wine become the body and blood of Christ. The Virgin Mary is venerated in the Eastern Orthodox Church as the God-bearer, honored in devotions.
The Oriental Orthodox Churches are a group of Eastern Christian churches adhering to Miaphysite Christology, with a total of approximately 60 million members worldwide. The Oriental Orthodox Churches are broadly part of the trinitarian Nicene Christian tradition shared by today’s mainstream churches, and represent one of its oldest branches.
As some of the oldest religious institutions in the world, the Oriental Orthodox Churches have played a prominent role in the history and culture of Armenia, Egypt, Eritrea, Ethiopia, Sudan, and some parts of Western Asia and India. An Eastern Christian body of autocephalous churches, its bishops are equal by virtue of episcopal ordination, and its doctrines can be summarized in that the churches recognize the validity of only the first three ecumenical councils.
The Oriental Orthodox Churches are composed of six autocephalous churches: the Coptic Orthodox Church of Alexandria, the Syriac Orthodox Church of Antioch, the Armenian Apostolic Church, the Malankara Orthodox Syrian Church, the Ethiopian Orthodox Tewahedo Church, and the Eritrean Orthodox Tewahedo Church.1 Collectively, they consider themselves to be the one, holy, catholic, and apostolic Church founded by Jesus Christ in his Great Commission, and that its bishops are the successors of Christ's apostles. Most member churches are part of the World Council of Churches. Three very different rites are practiced among the churches: the western-influenced Armenian Rite, the West Syriac Rite of the Syriac Church and the Malankara Church of India, and the Alexandrian Rite of the Copts, Ethiopians and Eritreans.
Oriental Orthodox Churches shared communion with the Imperial Roman Church before the Council of Chalcedon in 451 AD, as well as with the Church of the East until the Council of Ephesus in AD 431, all separating primarily over differences in Christology.
The main purpose of local church leaders is, first of all, to correctly grasp and comprehend the various moral teachings and theological beliefs of their own local churches, in which and by which they were raised, so that, when gathered together in a local council or synod, they might be able to properly bear witness to these, by faithfully describing them, and accurately representing their tenets.
They are not allowed to either misrepresent or singlehandedly reinterpret the faith to which they have been called as witnesses; nor subjectively substitute it with their own private and personal convictions; nor unilaterally impose the latter over the common orthodoxy of their respective churches, as it has been delivered unto them by their predecessors, and as they, in turn, have received it from their teachers in the faith, before becoming shepherds themselves.
The local bishop thus (i.e., as described above, and not in any different manner) presides over the local council, formed by the (married or monastic) priests of the various parishes and monasteries belonging to his own diocese; only to later pass on their joint conclusions along the chain of transmission, when himself called upon to report them to the holy synod, presided over by the country's patriarch; patriarchs then meet to discuss these conciliar decisions with each other, keeping the faith united, and pure from both heresy and immorality.