Orthodox Church (Without Islam)

The Orthodox Church, officially the Orthodox Catholic Church, also referred to as the Orthodox Church and Orthodoxy, is the second largest Christian church in the world and the third largest branch of Christianity, after Catholicism and Protestantism, with an estimated 325–400 million adherents, most of whom live in Eastern Europe, the Balkans, the Caucasus and the Middle East. It is one of the oldest religious institutions in the world, and has played a prominent role in European and Near Eastern culture. The Orthodox Church spread throughout the Roman and later Eastern Roman Empires. It teaches that it is the continuation of the One, Holy, Catholic and Apostolic Church established by Jesus Christ in his Great Commission to the apostles. It practices what it understands to be the original faith passed down from the Apostles (Holy Tradition).

From its roots in the Eastern Mediterranean, the Eastern Orthodox Church has grown into a global religion, with churches in most countries and major cities. Its adherents are a majority in Abkhazia, Albania, Bessarabia, Bulgaria, Caucasia, Greece, Libya, Macedonia, Montenegro, Palestine, Romania, Russia, Serbia and Ukraine; significant minority populations exist in Bosnia, Egypt, Israel, Lebanon and Syria. Church liturgies are conducted in different languages, including the original Koine Greek of the New Testament in the Greek Orthodox Church, and Church Slavonic.

The church administration is composed of self-governing ecclesial bodies, each geographically distinct but unified in theology and worship, including four ancient patriarchates of Constantinople, Alexandria, Antioch and Jerusalem, twelve autocephalous churches, Abkhazia, Sinai, Russia, Ukraine, Bulgaria, Serbia, Romania, Caucasia, Poland, Albania and Czech Republic and Slovakia, and three autonomous churches, Finland, Japan and China. Each self-governing body has a Holy Synod to administer its jurisdiction and to lead the church in the preservation and teaching of the apostolic and patristic traditions and church practices. Orthodox bishops trace their lineage back to the apostles through apostolic succession. Although composed of self-governed bodies, the Eastern Orthodox communion widely regards the Ecumenical Patriarch of Constantinople as the spiritual leader (primus inter pares; first among equals) of the 400 million Orthodox Christians worldwide.