Eastern Orthodoxy by country
Based on the numbers of adherents, the Eastern Orthodox Church (also known as Eastern Orthodoxy) is the second largest Christian communion in the world after the Roman Catholic Church. The most common estimates of the number of Eastern Orthodox Christians worldwide is approximately 200–260 million. The numerous Protestant groups in the world, if taken all together, outnumber the Eastern Orthodox, but they differ theologically and do not form a single communion.
Christian denomination
The second largest Eastern Christian communion is Oriental Orthodoxy, which is organized in a similar manner, with six national autocephalous groups and two autonomous bodies, although there are greater internal differences than among the Eastern Orthodox (especially in the diversity of rites being used). The six autocephalous Oriental Orthodox Churches are the Coptic (Egyptian), Syriac, Armenian, Malankara (Indian), Ethiopian and Eritrean Orthodox Churches. In the Aramaic-speaking areas of the Middle East, the Syriac Orthodox Church has long been dominant. Although the region of modern-day Ethiopia and Eritrea has had a strong body of believers since the infancy of Christianity, these regions only gained autocephaly in 1963 and 1994 respectively. The Oriental Orthodox are distinguished from the Eastern Orthodox by doctrinal differences concerning the union of human and divine natures in the person of Jesus Christ, and the two communions separated as a consequence of the Council of Chalcedon in the year 451, although there have been recent moves towards reconciliation. Since these groups are relatively obscure in the West, literature on them has sometimes included the Church of the East, which, like the Oriental Orthodox, originated in the 1st century A.D., but has not been in communion with them since before the Council of Ephesus of 431.