Russia, Ethiopia and Ukraine have largest national Orthodox populations

By Pew Research Center

Orthodox Christianity’s geographic center remains in Central and Eastern Europe

While the worldwide population of all non-Orthodox Christians has virtually quadrupled since 1910, the Orthodox population has merely doubled, from approximately 124 million to 260 million. And as the geographical center of the overall Christian population has shifted since 1910 from its centuries-old European base into developing nations in the Southern Hemisphere, most Orthodox Christians (roughly 200 million, or 76%) still live in Central and Eastern Europe (including Greece and the Balkans).

Indeed, nearly four-in-ten of the world’s Orthodox Christians live in a single country – Russia. During the Soviet era, millions of Russian Orthodox Christians moved to other parts of the Soviet Union, including Kazakhstan, Ukraine and the Baltic States, and many remain there today. Ukraine has both a substantial Russian Orthodox population and many members of its own self-governing Ukrainian Orthodox Church, with an estimated 35 million Orthodox Christians in total.

Ethiopia has a similarly large Orthodox population (36 million); its Orthodox Tewahedo Church claims lineage back to Christianity’s earliest centuries. Due to rapid population growth, Africa also has experienced a more recent increase in both the number and share of Orthodox Christians. In sub-Saharan Africa, the Orthodox population has risen more than tenfold over the last century, from an estimated 3.5 million in 1910 to 40 million in 2010. Sub-Saharan Africa, including a substantial Orthodox population in Eritrea as well as Ethiopia, now accounts for 15% of the Orthodox Christian population worldwide, up from 3% in 1910.

Meanwhile, there also are substantial populations of Orthodox Christians in the Middle East-North Africa region, mostly in Egypt (an estimated 4 million in 2010), with smaller numbers in Lebanon, Syria and Israel.

In all, 19 countries around the world have at least a million Orthodox Christians, including Romania (19 million) and Greece (10 million). Fourteen countries worldwide have Orthodox majorities, and all of them except Eritrea and Cyprus are in Europe. (In this report, Russia is classified as a European country.)

Most of the world’s 260 million Orthodox Christians live in Central and Eastern Europe

The doubling of the worldwide Orthodox Christian population to about 260 million has not kept pace with the growth rates of the global population – or of other Christian populations, which collectively have nearly quadrupled in size from 490 million in 1910 to 1.9 billion in 2010. (The total Christian population, including Orthodox, Catholics, Protestants and others, has risen from 614 million to 2.2 billion during that period.)

Central and Eastern Europe remains the main base for Orthodox Christians, and is home to more than three-quarters (76%) of them. An additional 15% live in sub-Saharan Africa, 4% live in the Asia-Pacific region, 2% live in the Middle East and North Africa, and about 1% live in Western Europe. Nearly 1% live in North America, while even fewer live in Latin America. This geographic distribution distinguishes Orthodox populations from the other major Christian groups, which are far more evenly distributed around the world.

Still, the share of Orthodox Christians living outside Central and Eastern Europe has increased somewhat, to 23% in 2010 from 9% a century ago. In 1910, only 11 million Orthodox Christians – out of a global Orthodox population of 124 million – were living outside the region. Now, there are 60 million Orthodox Christians living outside Central and Eastern Europe, out of a global Orthodox population of 260 million.

While the current share of Orthodox Christians living in Europe overall (77%) does represent a decline since 1910, when 91% of Orthodox Christians were living there, the share of the total Christian population living in Europe has decreased much more sharply, from 66% in 1910 to 26% in 2010. Indeed, nearly half (48%) of the broader Christian population now lives in Latin America and Africa, up from 14% in 1910.

One non-European part of the world that has experienced significant Orthodox population growth is sub-Saharan Africa, where the 15% share of the global Orthodox population is up from 3% in 1910. Most of the 40 million Orthodox Christians in this region live in Ethiopia (36 million) or Eritrea (3 million). At the same time, Orthodox Christians remain a small minority of sub-Saharan Africa’s Christians, most of whom are Catholics or Protestants.

Russia, Ethiopia and Ukraine have largest national Orthodox populations

In 1910, Russia’s Orthodox population was 60 million, but the number of Russians identifying as Orthodox dropped steeply during the Soviet era (to 39 million in 1970), when the Communist government was repressing religious worship and promoting atheism.8 Since the fall of the USSR, though, the number of Orthodox Christians in Russia has rebounded sharply, to more than 100 million.9

Results from a Pew Research Center survey conducted in 2015 suggest that the end of communism played a role in the rise of religion in this part of the world; more than half (53%) of Russians who say they were raised without religion but are now Orthodox cite an increasing societal acceptance as a major reason for their shift.

The second-largest Orthodox population in the world is found in Ethiopia, where Orthodox numbers have risen tenfold since the early 20th century, from 3.3 million in 1910 to 36 million in 2010. The overall population of Ethiopia has risen nearly tenfold during that timespan, from 9 million in 1910 to 83 million in 2010.

Ukraine’s Orthodox population (35 million) is nearly as big as Ethiopia’s. In all, 19 countries have Orthodox populations of 1 million or more.

Of the 10 countries with the largest Orthodox populations in 2010, eight are located in Central and Eastern Europe. In the two separate years for which data are available – 1910 and 2010 – the countries with the 10 largest Orthodox populations have remained mostly the same, with populations of the same nine countries ranking in the top 10 both times. Two additional countries each made the list once: Turkey in 1910 and Egypt in 2010.

There are 14 Orthodox-majority countries in the world, and all are located in Europe except for Eritrea, which is in sub-Saharan Africa, and Cyprus, which is categorized in the Asia-Pacific region in this report. (Ethiopia’s 36 million Orthodox Christians are not a majority; they comprise about 43% of Ethiopia’s population.)

The country with the highest percentage of Orthodox Christians is Moldova (95%). In Russia, the largest of the Orthodox-majority countries, about seven-in-ten people (71%) are Orthodox. The smallest country with an Orthodox majority is Montenegro (which has a total population of 630,000), where 74% of the population is Orthodox.10

 Orthodox diasporas have developed in Americas and Western Europe

Over the last century, several sizable diaspora communities of Orthodox Christians have developed in the Americas and Western Europe, areas that, a century ago, had only small Orthodox populations.

There are seven countries in Western Europe that had fewer than 10,000 Orthodox Christians in 1910 but now have Orthodox populations over 100,000. The largest of these are Germany, which had just a few thousand Orthodox Christians in 1910 and now has 1.1 million, and Spain, which had no Orthodox community to speak of in 1910 and now has 900,000 Orthodox Christians.

In the Americas, there are three countries with over 100,000 Orthodox Christians that had fewer than 20,000 a century ago: Canada, Mexico and Brazil. The United States, which has 1.8 million Orthodox Christians, already had 460,000 in 1910.

Orthodoxy in the United States

The presence of Orthodox Christians within the present boundaries of the United States dates to 1794, when a small group of Russian missionaries arrived in Kodiak, Alaska, to proselytize its inhabitants. This missionary work continued during the 1800s, but the bulk of Orthodoxy’s growth in the United States owes to late 19th- and early 20th-century immigration from countries across Central and Eastern Europe.11 By 1910 nearly half a million Orthodox Christians lived in the United States, and in 2010 the figure was approximately 1.8 million – about half of 1% of the U.S. population.

The Orthodox presence in the U.S. is a fragmented one. The population’s splintered state across more than 21 denominations reflects varied ethnic ties to countries around the world with their own self-governing Orthodox patriarchates.12 Nearly half (49%) of U.S. Orthodox Christians identify as Greek Orthodox, 16% as Russian Orthodox, 3% as Armenian Orthodox, 3% as Ethiopian Orthodox and 2% as Coptic/Egyptian Orthodox. In addition, 10% identify with the Orthodox Church in America, a self-governing denomination based in the United States that, despite its Russian and Greek roots, has many parishes that are predominantly Albanian, Bulgarian and Romanian. Another 8% of Orthodox Christians in the U.S. say they are Orthodox without specifying further (6%) or are ambiguous about their affiliation (2%).13

In all, nearly two-thirds (64%) of U.S. Orthodox Christians are either immigrants (40%) or the children of immigrants (23%), the highest such share of any Christian denomination in the United States.14 Other than the U.S., some of the most common birthplaces for U.S. Orthodox Christians are Russia (5% of the total U.S. Orthodox population), Ethiopia (4%), Romania (4%) and Greece (3%).

By common measures of religiosity, Orthodox Christians in the United States are somewhat less likely than most other American Christian groups to say religion is very important in their lives (52%) and to say they attend church at least once a week (31%). By comparison, 68% of U.S. Christians overall say religion is very important to them and 47% say they are weekly churchgoers.

It is Africa, though, that has seen the largest Orthodox population growth outside of Central and Eastern Europe. Ethiopia, where the Orthodox population has increased over the last century from 3 million to 36 million, is not part of an Orthodox diaspora; its Orthodox history dates to the fourth century of Christianity, more than half a millennium before Christianity developed a substantial following in Russia. The growth in Ethiopia’s Orthodox population over the last century, as well as in neighboring Eritrea, owes largely to natural population growth in the countries. Orthodox Christianity in Kenya, on the other hand, developed during the early to mid-20th century through the assistance of missionaries and became affiliated with the Eastern Orthodox Patriarchate of Alexandria and All Africa in the 1960s.15

Orthodox Christianity in the 21st Century

Concentrated in Europe, Orthodox Christians have declined as a percentage of the global population, but Ethiopian community is highly observant and growing

Mgvimevi Monastery church, near the city of Chiatura in the Imereti region of Georgia.

Mgvimevi Monastery church, near the city of Chiatura in the Imereti region of Georgia.

Over the last century, the Orthodox Christian population around the world has more than doubled and now stands at nearly 260 million. In Russia alone, it has surpassed 100 million, a sharp resurgence after the fall of the Soviet Union.

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. Today, just 12% of Christians around the world are Orthodox, compared with an estimated 20% a century ago. And 4% of the total global population is Orthodox, compared with an estimated 7% in 1910.

The geographic distribution of Orthodoxy also differs from the other major Christian traditions in the 21st century. In 1910 – shortly before the watershed events of World War I, the Bolshevik revolution in Russia and the breakup of several European empires – all three major branches of Christianity (Orthodoxy, Catholicism and Protestantism) were predominantly concentrated in Europe. Since then, Catholics and Protestants have expanded enormously outside the continent, while Orthodoxy remains largely centered in Europe. Today, nearly four-in-five Orthodox Christians (77%) live in Europe, a relatively modest change from a century ago (91%). By contrast, only about one-quarter of Catholics (24%) and one-in-eight Protestants (12%) now live in Europe, down from an estimated 65% and 52%, respectively, in 1910.1

Orthodoxy’s falling share of the global Christian population is connected with demographic trends in Europe, which has lower overall fertility rates and an older population than developing regions of the world, such as sub-Saharan Africa, Latin America and South Asia. Europe’s population has long been shrinking as a share of the world’s total population, and, in coming decades, it is projected to decline in absolute numbers as well.

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. Orthodoxy came first to Bulgaria, Serbia and Moravia (which is now part of the Czech Republic), and then, beginning in the 10th century, to Russia. Following the Great Schism between the Eastern (Orthodox) churches and the Western (Catholic) church in 1054, Orthodox missionary activity expanded across the Russian Empire from the 1300s through the 1800s.2

While Orthodoxy spread across the Eurasian landmass, Protestant and Catholic missionaries from Western Europe went overseas, crossing the Mediterranean and the Atlantic. 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.3

Today, the largest Orthodox Christian population outside of Eastern Europe is in Ethiopia. The centuries-old Ethiopian Orthodox Tewahedo Church has an estimated 36 million adherents, nearly 14% of the world’s total Orthodox population. This East African outpost of Orthodoxy reflects two broad trends. First, its Orthodox Christian population has grown much faster than Europe’s over the past 100 years. 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. (This is true not just of Christianin Europe but also of Europe’s Muslims, who are less religiously observant, as a whole, than Muslims elsewhere in the world.)

Fewer Orthodox in post-Soviet republics say religion ‘very important’ in their lives

Orthodox Christians in the former Soviet Union generally report the lowest levels of observance among those of their faith, perhaps reflecting the legacy of Soviet repression of religion. In Russia, for example, just 6% of Orthodox Christian adults say they attend church at least weekly, 15% say religion is “very important” in their lives, and 18% say they pray daily. Other former Soviet republics display similarly low levels of religious observance. Together, these countries are home to a majority of the world’s Orthodox Christians.

In sharp contrast, Orthodox Christians in Ethiopia report considerably higher religious observance, on par with other Christians (including Catholics and Protestants) across sub-Saharan Africa. Nearly all Ethiopian Orthodox Christians say religion is very important to them, while roughly three-quarters report attending church weekly or more often (78%) and about two-thirds say they pray daily (65%). (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.

Orthodox Christians in the United States, who make up roughly 0.5% of the overall U.S. population and include many immigrants, display moderate levels of religious observance, lower than in Ethiopia but higher than most European countries, at least by some measures. About half (52%) of Orthodox Christian adults in the United States say religion is very important to them, roughly one-in-three (31%) report that they attend church weekly or more, and a slim majority say they pray daily (57%).

In addition to their shared history and liturgical traditions, what do these disparate communities have in common today?

One nearly universal practice among Orthodox Christians is the veneration of religious icons. Most Orthodox Christians around the world say they keep icons or other holy figures in their homes.

In fact, having icons is among the few indicators of religiosity on which Central and Eastern European Orthodox Christians surpass Orthodox Ethiopians in surveys. 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.

These are among the key findings of a new Pew Research Center study of Orthodox Christianity around the world. The data in this report come from a variety of surveys and other sources. Data on the religious beliefs and practices of Orthodox Christians in nine countries across the former Soviet Union and five other countries in Europe, including Greece, are from surveys conducted by Pew Research Center in 2015-2016. In addition, the Center has recent data on many (though not all) of the same survey questions among Orthodox Christians in Ethiopia and the United States. Together, these surveys cover a total of 16 countries, collectively representing about 90% of the estimated global Orthodox population. In addition, population estimates are available for all countries based on information gathered for the 2011 Pew Research Center report “Global Christianity” and the 2015 report “The Future of World Religions: Population Growth Projections, 2010-2050.”

Wide support among Orthodox for the church’s teachings on priesthood, divorce

While they vary widely in their levels of religious observance, Orthodox Christians around the world are largely united in their affirmation of some distinctive church policies and teachings.

Today, majorities of Orthodox Christians in every country surveyed say they favor their church’s current practice of allowing married men to become priests, which contrasts with the Catholic Church’s general requirement of celibacy for priests. (Lay Catholics in some countries prefer allowing married priests; in the United States, for example, 62% of Catholics say the Catholic Church should allow priests to get married.)

Similarly, most Orthodox Christians also say they support the church’s stance on recognizing divorce, which also differs from Catholicism’s position.

On balance, Orthodox Christians favor their church’s prohibition on female priests


Orthodox Christians also broadly favor a number of church positions that happen to align with those of the Catholic Church, such as the prohibition on women’s ordination. In fact, there appears to be more agreement with this position within Orthodoxy than within Catholicism, where majorities in some places say women should be able to become priests. For example, in Brazil, which has the world’s largest Catholic population, most Catholics say the Catholic Church should allow female ordination (78%). Similarly, in the United States, 59% of Catholics say the Catholic Church should allow women priests.

Orthodox opinion is closely divided on the issue of female ordination in Russia and some other countries, but in no country surveyed do a majority of Orthodox Christians support ordaining women as priests. (In Russia and some other countries, roughly a fifth or more of respondents do not express an opinion on women’s ordination.)

Orthodox Christians also are broadly united against the idea of the church performing same-sex marriages (see Chapter 3).

Relatively low shares of Orthodox and Catholics favor Eastern Orthodoxy and Roman Catholicism being in communionOverall, Orthodox Christians see plenty of common ground between their own faith and Catholicism. When asked if Orthodoxy and Roman Catholicism “have a lot in common” or “are very different,” most Orthodox Christians across Central and Eastern Europe respond that the two faiths have a lot in common. For their part, Catholics in the region also tend to see the two traditions as more similar than different.

But this perceived kinship only goes so far; there is limited support among Orthodox Christians for “being in communion again” with Roman Catholics. Formal schism owing to theological and political disputes has divided Eastern Orthodoxy from Roman Catholicism since the year 1054; while some clerics on both sides have tried for half a century to foster reconciliation, the view that the churches should reunite is a minority position across most of Central and Eastern Europe.4

In Russia, just one-in-six Orthodox Christians (17%) say they want Eastern Orthodoxy to be in communion with the Roman Catholic Church, the lowest level of support for reconciliation found in any of the national Orthodox populations surveyed. Only in one country, Romania, do a majority of respondents (62%) express support for reunification of the Eastern and Western churches. Across the region, many Orthodox Christians decline to answer this question, perhaps reflecting a lack of familiarity with the issue or uncertainty about what communion between the two churches would entail.

This pattern may be linked to a wariness of papal authority by Orthodox Christians. While most Orthodox Christians across Central and Eastern Europe say Pope Francis is improving relations between Catholics and Orthodox Christians, far fewer express a positive opinion of Francis overall. Views on this topic also may be bound up with geopolitical tensions between Eastern and Western Europe. Orthodox Christians in Central and Eastern Europe tend to orient themselves, both politically and religiously, toward Russia, while Catholics in the region generally look toward the West.

Overall, in Central and Eastern Europe, Orthodox support for reconciliation with Catholicism is about as high as Catholic support for it. But in countries with substantial shares of both Orthodox Christians and Catholics, Catholics tend to be more supportive of a return to communion with Eastern Orthodoxy. For example, in Bosnia, a majority of Catholics (68%) favor communion, compared with a minority (42%) of Orthodox Christians. A similar pattern is seen in Ukraine and Belarus.

Sidebar: Eastern Orthodoxy vs. Oriental Orthodoxy

Not only are there important theological and doctrinal differences among Orthodox Christians, Catholics and Protestants, but there also are differences within Orthodoxy, which conventionally is divided into two major branches: Eastern Orthodoxy, most of whose adherents live in Central and Eastern Europe, and Oriental Orthodoxy, most of whose adherents live in Africa.

One theological difference has to do with the nature of Jesus and how to articulate Jesus’s divinity – part of a theological field of study called Christology. Eastern Orthodoxy, as well as Catholicism and Protestantism, teach that Christ is one person in two natures: both fully divine and fully human, accepting the language from an early Christian gathering called the Council of Chalcedon, held in 451. But Oriental Orthodoxy, which is considered “non-Chalcedonian,” teaches that Christ’s divine and human natures are unified, not separated.5

Oriental Orthodoxy has separate self-governing jurisdictions in Ethiopia, Egypt, Eritrea, India, Armenia and Syria, and it accounts for roughly 20% of the worldwide Orthodox population. Eastern Orthodoxy is split into 15 jurisdictions heavily centered in Central and Eastern Europe, accounting for the remaining 80% of Orthodox Christians.6

Data on the beliefs, practices and attitudes of Orthodox Christians in Europe and the former Soviet Union come from surveys conducted between June 2015 and July 2016 through face-to-face interviews in 19 countries, including 14 for which samples of Orthodox Christians were large enough for analysis. Findings from these surveys were released in a major Pew Research Center report in May 2017, but additional analysis (including results from Kazakhstan, which were not included in the initial report) is included throughout this report.

Orthodox Christians in Ethiopia were polled as part of Pew Research Center’s 2015 Global Attitudes survey, as well as a 2008 survey on religious beliefs and practices of Christians and Muslims in sub-Saharan Africa; Orthodox Christians in the U.S. were surveyed as part of Pew Research Center’s 2014 U.S. Religious Landscape Study. Since the methodology and the mode of the U.S. study are different from surveys conducted in other countries, comparisons between them are made cautiously. In addition, due to differences in questionnaire content, data are not available from all countries for every question analyzed in this report.

The largest Orthodox populations that were not surveyed are in Egypt, Eritrea, India, Macedonia and Germany. Despite the lack of survey data on Orthodox Christians in these countries, they are included in the population estimates in this report.

Although Orthodox Christians comprise roughly 2% of the Middle East’s population, logistical concerns make it difficult to survey these groups. Egypt has the Middle East’s largest Orthodox population (an estimated 4 million Egyptians, or 5% of the population), mainly members of the Coptic Orthodox Church. Additional data on the demographic characteristics of Middle Eastern Orthodox Christians, including their declining shares over time, can be found in Chapter 1.

Historical population estimates for 1910 are based on Pew Research Center analysis of data from the World Christian Database, which was compiled by The Center for the Study of Global Christianity at the Gordon-Conwell Theological Seminary. The estimates from 1910 provide a vantage point on worldwide Orthodoxy at an important historical moment, preceded by an especially active period for Orthodox missionaries across the Russian Empire and shortly before war and political upheaval threw most Orthodox populations into tumult.7 By the end of the 1920s, the Russian, Ottoman, German and Austro-Hungarian empires had all ceased to exist – replaced by new, self-governing nations, as well as, in some cases, self-governing national Orthodox churches. Meanwhile, the Russian Revolution of 1917 ushered in communist governments that persecuted Christians and other religious groups for the length of the Soviet era.

This report, funded by The Pew Charitable Trusts and the John Templeton Foundation, is part of a larger effort by Pew Research Center to understand religious change and its impact on societies around the world. The Center previously has conducted religion-focused surveys across sub-Saharan Africa; the Middle East-North Africa region and many other countries with large Muslim populations; Latin America and the Caribbean; Israel; and the United States.

Other key findings in this report include:

  • Orthodox Christians in Central and Eastern Europe widely favor protecting the natural environment for future generations, even if this reduces economic growth. In part, this view may be a reflection of the environmentalist stance of Patriarch Bartholomew of Constantinople, who is considered a theological authority in Eastern Orthodoxy. But environmentalism seems to be a widespread value across the Central and Eastern European region as a whole. Indeed, a majority of Catholics in the region also say the natural environment should be protected, even if this reduces economic growth. (For more details, see Chapter 4.)
  • Most Orthodox-majority countries in Central and Eastern Europe – including Armenia, Bulgaria, Georgia, Greece, Romania, Russia, Serbia and Ukraine – have national patriarchs who are regarded as preeminent religious figures in their home countries. In all but Armenia and Greece, pluralities or majorities see the national patriarchs as the highest authority of Orthodoxy. For example, in Bulgaria, 59% of Orthodox Christians say they recognize their national patriarch as the highest authority of the church, although 8% also point to Patriarch Bartholomew of Constantinople, who is known as the ecumenical patriarch across Eastern Orthodoxy. Patriarch Kirill of Russia also is highly regarded among Orthodox Christians in the region – even outside Russian borders – a trend that is in line with Orthodox Christians’ overall affinity for Russia. (For Orthodox Christians’ views on patriarchs, see Chapter 3.)
  • U.S. Orthodox Christians are much more accepting of homosexuality than are Orthodox Christians in Central and Eastern Europe and Ethiopia. About half of U.S. Orthodox Christians (54%) said same-sex marriage should be legal in a 2014 survey, similar to the share of Americans overall who took that position in that year (53%). By comparison, the vast majority of Orthodox Christians across Central and Eastern Europe are opposed to same-sex marriage. (For Orthodox Christians’ views on social issues, see Chapter 4.)
    • Overwhelming majorities of Orthodox Christians in Central and Eastern Europe say they have been baptized, even though many came of age during Soviet times. (For more on religious practices of Orthodox Christians, see Chapter 2.)

Correction: The chart “Relatively low shares of Orthodox and Catholics favor Eastern Orthodoxy and Roman Catholicism being in communion” has been updated to correct the share of Catholics in Bosnia saying the two churches should be in communion.  

Correction: The chart “A century ago, all three major branches of Christianity were concentrated in Europe. That is still the case for Orthodox Christians, but not Protestants and Catholics” has been updated to correct the share of Orthodox living in Asia-Pacific in 2010.


  1. Population figures for 2010 are based on Pew Research Center analysis of numerous censuses and surveys, including Pew Research Center’s 2011 report, “Global Christianity: A Report on the Size and Distribution of the World’s Christian Population.” The 1910 estimates are derived from Johnson, Todd M. and Gina A. Zurlo, eds. “World Christian Database.” Center for the Study of Global Christianity at Gordon-Conwell Theological Seminary, accessed April 2017. 
  2. According to church tradition, the two best known Byzantine missionaries were brothers named Cyril and Methodius, who are saints in the Orthodox Church and who have been called “Apostles to the Slavs.” See Tachiaos, Anthony Emil N. 2001. “Cyril and Methodius of Thessalonica: The Acculturation of the Slavs.” Also see Veronis, Luke A. 1994. “Missionaries, Monks and Martyrs: Making Disciples of All Nations.” Also see Herrin, Judith. 2008. Byzantium: The Surprising Life of a Medieval Empire.” At the time of these ninth-century missions, Christianity in Central and Eastern Europe was not yet called Orthodoxy. The group became known as Orthodox Christians after the Great Schism of 1054 divided most of the era’s Christian world between its Latin West and its Greek East. High among the dividing issues was a dispute over papal authority; the Western Church (now called Roman Catholic) contended that the pope’s religious authority over Christians was universal. The Eastern Church (now called Eastern Orthodox) disagreed, investing their highest religious authority in various patriarchs across the Eastern Orthodox world, with the ecumenical patriarch of Constantinople traditionally holding the title “first among equals.” 
  3. See Veronis, Luke A. 2008. “Eastern Orthodox Missions.” In “Encyclopedia of Christianity Online.” Also see Stokoe, Mark and Leonid Kishkovsky. 1995. “Orthodox Christians in North America (1794-1994).” 
  4. Orthodox-Catholic relations began improving just over a half-century ago, in January 1964, when Pope Paul VI and Ecumenical Patriarch Athenagoras met in Jerusalem. In December 1965 they lifted mutual excommunications from the year 1054 that had long helped define the schism. Since then, many clerics from both traditions have worked to ease tensions. See the Dec. 7, 1965, statement, “Joint Catholic-Orthodox Declaration of His Holiness Pope Paul VI and the Ecumenical Patriarch Athenagoras I.” 
  5. Hastings, Adrian. 1999. “150-550.” In Hastings, Adrian, ed. “A World History of Christianity.” Also see Kirkorian, Mesrob K. 2010. “Christology of the Oriental Orthodox Churches: Christology in the Tradition of the Armenian Apostolic Church.” 
  6. One of these 15 jurisdictions is the Orthodox Church in America, which is not universally recognized as its own jurisdiction by Eastern Orthodox churches. 
  7. See Veronis, Luke A. 2008. “Eastern Orthodox Missions.” In “Encyclopedia of Christianity Online.” 
  1. Johnson, Todd M. and Gina A. Zurlo, eds. “World Christian Database.” Center for the Study of Global Christianity at Gordon-Conwell Theological Seminary, accessed June 2017. 
  2. See Pew Research Center’s 2014 report, “Russians Return to Religion, But Not to Church.” 
  3. Orthodox population and percentage figures are based on Pew Research Center analysis of census and survey data. See Methodology for details. 
  4. Stokoe, Mark and Leonid Kishkovsky. 1995. “Orthodox Christians in North America (1794-1994).” 
  5. They include, for example, the Greek Orthodox Archdiocese in America, the Holy Orthodox Church in North America, the Patriarchal Parishes of the Russian Orthodox Church in the USA, and the Malankara Orthodox Syrian Church, among others. 
  6. See Pew Research Center’s 2014 U.S. Religious Landscape Study
  7. The highest such level among U.S. religious groups is found among Hindus, 96% of whom are either immigrants (87%) or second-generation Americans (9%). See Pew Research Center’s 2014 U.S. Religious Landscape Study
  8. Githieya, Francis Kimani. 1997. “The Freedom of the Spirit: African Indigenous Churches in Kenya.” 


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