The Portuguese, Spanish, Dutch and British empires, among others, carried Western Christianity (Catholicism and Protestantism) to sub-Saharan Africa, East Asia and the Americas – regions that in the 20th century experienced much faster population growth than Europe.On the whole, Orthodox missionary activity outside Eurasia was less pronounced, although Orthodox churches retained footholds through the centuries in the Middle East, and Orthodox missionaries won some converts in such far-flung places as India, Japan, East Africa and North America.And, second, Orthodox Christians in Ethiopia are more religiously observant, by several common measures, than Orthodox Christians in Europe.This is in line with a broader pattern in which Europeans are, on average, less religiously committed than people in Latin America and sub-Saharan Africa, according to Pew Research Center surveys.Historically, the presence of what is now called Orthodox Christianity in the Slavic portions of Eastern Europe dates to the ninth century, when, according to church tradition, missionaries from the Byzantine Empire’s capital in Constantinople (now Istanbul, Turkey) spread the faith deeper into Europe.
The geographic distribution of Orthodoxy also differs from the other major Christian traditions in the 21st century.Across 14 countries in the former Soviet Union and elsewhere in Europe with large Orthodox populations, the median share of Orthodox Christians who say they have icons at home is 90%, while in Ethiopia, the share is 73%.Orthodox Christians around the world also are linked by a married, all-male priesthood; church structures headed by numerous national patriarchs and archbishops; recognition of divorce; and moral conservatism on issues such as homosexuality and same-sex marriage.(For more information on Ethiopia’s Orthodox Tewahedo Church, see this sidebar.) Orthodox Christians living in Europe outside the former Soviet Union show somewhat higher levels of religious observance than those in the former Soviet republics, but they are still far less observant than Ethiopia’s Orthodox community.In Bosnia, for example, 46% of Orthodox Christians say religion is very important in their lives, while 10% say they attend church weekly or more often, and 28% report that they pray daily.
Yet despite these increases in absolute numbers, Orthodox Christians have been declining as a share of the overall Christian population – and the global population – due to far faster growth among Protestants, Catholics and non-Christians.