Ostkirchen

Ostkirchen, or Eastern Churches, is a term used to describe Christian churches whose liturgical and theological traditions originated in the East and which are distinct from the Latin Western tradition of the Roman Catholic Church. The designation encompasses three main families: the Eastern Orthodox Churches, the Oriental Orthodox Churches, and the Eastern Catholic Churches that are in communion with Rome.

The Eastern Orthodox Churches consist of autocephalous or autonomous jurisdictions sharing a common heritage, including the Ecumenical Patriarchate of Constantinople as a primus inter pares, along with the Russian, Greek, Romanian, Serbian, and other national churches. They follow the Byzantine rite and use liturgical languages such as Greek, Church Slavonic, and others. The Oriental Orthodox Churches, often called Non-Chalcedonian, remained separate after the Council of Chalcedon in 451; major members include the Coptic Orthodox Church, the Syriac Orthodox Church, the Armenian Apostolic Church, and the Ethiopian and Eritrean Orthodox Tewahdo Churches, as well as the Malankara Orthodox Syrian Church. They preserve distinct rites, such as Coptic, Syriac, and Armenian, and are not in full communion with the Eastern Orthodox.

The Eastern Catholic Churches consist of a number of communities that are in full communion with the Pope while preserving their own liturgical rites and canon law, including the Ukrainian Greek Catholic Church, the Melkite Greek Catholic Church, the Maronite Church, and the Syro-Malabar and Syro-Malankara Churches. They maintain Eastern liturgical traditions such as the Byzantine, Alexandrian, and Antiochian rites.

Historically rooted in the Christian East, Ostkirchen have played a central role in the religious, cultural, and political development of Europe, the Middle East, and the Caucasus. The Great Schism of 1054 formalized a separation between most Eastern Orthodox and Western Latin Christendom, while the Chalcedonian split divided Oriental Orthodox from both. In modern times, dialogue and cooperation with Western churches continue alongside distinct governance, rites, and languages within each tradition.