The Middle East is the birthplace of Christianity and home to some of the world's most ancient Christian denominations. But Christian communities across the region are declining in numbers because of a combination of low birth rates, emigration and, in some places, persecution.
Lebanon is the only Middle Eastern country where Christians were once dominant and retain considerable political power.
The country's religious breakdown is deeply sensitive as the country's 1975-1989 civil war was fought largely along religious lines.
Total population: 4m
Estimated Christians: 1.35m-1,6m
% Christian: 34-41%
Main churches: Maronite, Greek Orthodox
Issues: Political change
The last official census was done in 1932, but current estimates suggest there are slightly more Muslims than Christians. There is a widespread perception among Christians that their numbers and influence are declining.
The constitution dictates that the president is always Christian, the prime minister Sunni Muslim, and the parliamentary speaker Shia Muslim.
The largest church is the Maronite Church, which traces its origins to a 4th Century Syrian hermit, St Maron. The church united with the Catholic Church in 1736, although it retains its own traditions and practices.
The Greek Orthodox church is also strong in Lebanon, and there is a wide range of other denominations. Most religious groups operate freely.
Muslim-Christian relations have generally been calm in recent years. However, general political tensions in the country increased in 2005 with the assassination of former Prime Minister Rafik Hariri, the withdrawal of Syrian troops and a wave of bombings in Christian areas.
Sources: The CIA World Factbook estimates that 39% of Lebanon's population is Christian. Al-Nahar, a major national daily newspaper estimated in 2005 that Christians made up 40.8% of the population. The World Christian Database says there are approximately 1,350,000 Christians. UNDP estimates the country's population to be 4m.
About 19% of the country's population are Israeli-Arab - and about 9% of those are Christian.
As such the Christians are a minority within a minority, facing both the well-documented discrimination that all Israeli-Arabs are subject to and also the struggle to maintain their identity as part of an overwhelmingly Muslim population group.
Total population: 6.8m
Estimated Christians: 144,000-196,000
% Christian: 2.1-2.8%
Main churches: Greek Orthodox, Catholic
Issues: Discrimination against Arabs, falling numbers
The majority are from Catholic - both Eastern and Western rite - denominations and the Greek Orthodox church.
The remaining Christians include increasing numbers of immigrants from around the world. A vast number of denominations are represented, including Copts, Armenians, Russian Orthodox, Lutherans and a wide range of other Protestant groups.
There are also Messianic Jews who consider themselves Jewish but recognise Christ as the Messiah, and Christian Zionists who profess strong support the Jewish people.
Although there are some inequalities in the treatment of different religious groups in the predominantly Jewish state, there is full freedom of worship and proselytising is allowed.
Sources: Government figures put the Israeli Christian population at 144,000, of which 117,000 are Christian Arabs. The World Christian Database, working mainly from church estimates, puts the total 50,000 higher. This may be partly due to an estimated 100,000 illegal workers in the country, many of whom are Christian. The World Bank estimates Israel's population to be 6.8m.
WEST BANK AND GAZA
Christian communities in the West Bank and Gaza have been declining for several decades because of conflict, economic decline and low birth rates.
The World Christian Database says they accounted for 5.3% of the population in 1970 and have dropped to less than half that now.
WEST BANK AND GAZA CHRISTIANS
Total population: 3.76m
Estimated Christians: 40,000-90,000
% Christian: 1.1-2.4%
Main churches: Greek Orthodox and Catholic
Issues: Falling numbers, economic decline, occupation
Some Christian leaders also cite the rise of radical Islam in the area as a growing pressure on Christian communities.
Christians are concentrated in and around the towns of Bethlehem and Ramallah. A pastor in Gaza City estimates there are a mere 2,000 Christians among the Gaza Strip's 1.3 million in habitants.
The two largest churches are the Greek Orthodox and Catholic churches, although the Assyrian, Armenian Orthodox and Syrian Orthodox churches, as well as many Protestant denominations, are also represented.
Christian-Muslim relationships are largely peaceful and Christians have reached senior positions in the Palestinian Authority, although some Palestinian Christians complain of harassment and discrimination.
Sources: The most recent PA census in 1997 recorded just over 40,000 Christians. The World Christian Database says there are about 90,000. The Palestinian Authority says the population of Gaza and the West Bank is 3.76 million.
Most Christians in Egypt are Copts - Christians descended from the ancient Egyptians.
Their church split from the Eastern Orthodox and Roman Catholic churches in 451AD because of a theological dispute over the nature of Christ, but is now, on most issues, doctrinally similar to the Eastern Orthodox church.
Total population: 68.7m
Estimated Christians: 5.8m-11m
% Christian: 8-16%
Main church: Coptic Orthodox
Issues: Some discrimination
The Coptic language - a descendent of the ancient Egyptian language, written mainly in the Greek alphabet - is still used for small parts of services.
Although Christian-Muslim relations are relatively peaceful, Copts complain of discrimination in the workplace and restrictions on church construction, and are concerned that new electoral rules are benefiting Islamist parties but not increasing Coptic political representation.
A plethora of other Catholic, Orthodox, Protestant and Armenian churches are present in smaller numbers in Egypt.
Sources: The Egyptian government estimates there are 5.6 million Christians; church estimates rise to 11 million.
Syria has for much of the century had a sizeable Christian minority making up at least 10% of the population. The proportion is thought to be declining due to emigration and low birth rates, although there are few reliable statistics.
Total population: 18.1m
Estimated Christians: 970,000-1.7m
% Christian: 5.4-9.4%
Main church: Greek Orthodox, Catholic
Issues: Declining numbers
In recent years Syria has been considered one of the easier Middle Eastern countries for Christians to live in. Power is concentrated in the hands of the Alawite minority - a Shia sect considered heretical by many Muslims - who have clamped down hard on extreme forms of Islam.
Although some Christians have been successful in professions and business - with a few rising relatively high in the administration - others have followed relatives to the West for economic reasons or to escape the general repression of the regime.
The largest churches are the Greek Orthodox and Greek Catholic churches. There are also Syrian Orthodox, Syrian Catholic, Armenian Orthodox, Armenian Catholic, Assyrian and Chaldean (see Iran and Iraq) Christians.
Sources: The World Christian Database put the number of Christians at 970,000, while a US State Department report says there are 1.7m. According to UNDP, the population is 18.1m.
Jordan's Christian population has dropped from about 5% of the population in 1970 to the current estimated 3%.
The main churches are Eastern and Western-rite Catholic and the Greek Orthodox church.
Total population: 5.4m
Estimated Christians: 163,000-220,000
% Christian: 3-4%
Main churches: Catholic, Greek Orthodox
Issues: Declining numbers
There is generally freedom of religion, apart from for Muslims converting to Christianity who sometimes face severe discrimination.
All churches must be recognised by the government. Nine of the 110 parliamentary seats are reserved for Christians. There are many missionary groups in the country, although proselytising Muslims is not allowed.
Relations between Christians and Muslims are amicable and Christians do not generally face discrimination, according to a US Department of State report.
Sources: Official government figures estimate that 4% of the population is Christian, although according to a US State Department report, government and Christian officials privately estimate the true figure to be closer to 3%. The World Christian Database estimates the Christian population to be 168,000. The World Bank puts the population at 5.4m.
There has been a Christian presence in what is now Iraq since the 2nd Century. The largest groups are the Chaldean and Assyrian churches, which are descended form similar roots but generally seen as separate ethnic groups. IRAQ'S CHRISTIANS
Total population: 27.3
Estimated Christians: 700,000-1m
% Christian: 2.7- 3.5%
Main churches: Chaldean, Assyrian
Issues: Falling numbers, security
The Chaldeans are Eastern-rite Catholics - autonomous churches of Eastern origin which retain their own liturgy and traditions, but recognise the Pope's authority.
The Assyrian church - the Ancient Church of the East, also sometimes referred to as the Nestorian church - traces its roots back to 2nd Century Mesopotamia and is not Catholic.
The traditional liturgical language of both Assyrian and Chaldean churches is Syriac - a descendent of Aramaic, the language thought to have been spoken by Jesus and his disciples. Some Iraqi Christians still speak Syriac.
Iraq also has communities of Syrian Catholics, Syrian Orthodox, Copts, Armenian Orthodox, Armenian Catholics, Greek Orthodox and Greek Catholics, as well as Anglicans and Evangelicals.
A rise in attacks on Christians since the US-led invasion in 2003 has prompted many to leave, although estimates that some 40,000 - 60,000 have left cannot be confirmed.
Although the Iraqi government has made commitments to enshrining the rights of religious minorities in the country's new constitution, the lack of security makes these difficult to enforce on the ground.
Sources: The World Christian Database says there are about 700,000 Christians in Iraq, while estimates from local church leaders and a US government report put the figure close to a million. There were 1.4 million in 1987 when the country's last census was conducted under Saddam Hussein. The UNDP estimates the total population to be 27.3 million.
The largest church in Iran is the Armenian Apostolic Church, which dates back to around 300AD.
Its doctrines are similar to the Eastern Orthodox Church, although services follow traditional Armenian rites and the Armenian language is used.
Total population: 66.9m
Estimated Christians: 79,000-400,000
% Christian: 0.1-0.6%
Main church: Armenian
Issues: Declining numbers, discrimination
There has been an Armenian community in Iran for several centuries.
The second largest church is the Assyrian church (see Iraq).
Iran's traditional Christian populations are recognised in the constitution, guaranteed freedom to worship and allocated seats in the parliament, but face some discrimination in employment and political rights.
Numbers are thought to be decreasing.
Evangelical Christians are not recognised and face heavy discrimination.
Sources: The World Christian Database estimates the Christian population at 400,000, although the most recent government census (1996) puts the figure at 79,000. The UN Special Representative for Iran estimated there were 300,000 Christians in 2001, but that 15,000 - 20,000 were leaving every year.
All the Gulf countries have very few, if any, indigenous Christians. Most, however, have large populations of expatriate workers from around the world, many of which include sizeable Christian communities.
In most countries the expatriates have freedom of worship but are not allowed to try to convert Muslims to Christianity. In Saudi Arabia, public ex
World Christian Database figures include several thousand Arab Christians in isolated churches linked by TV or radio networks in the UAE, Oman, Saudi Arabia and Yemen - and another 13,000 "hidden Muslim believers" in Saudi Arabia. All figures are estimates derived from the claims of Christian organisations.
CHRISTIANS IN THE GULF STATES
Foreign workers: 270,000
Foreign workers: 500,000
Foreign workers: >7m
Yemen: Population: 20m
Foreign workers: unknown
Christians: 3,000 - 38,000
Foreign workers: 1.8m
Foreign workers: 544,000
Foreign workers: 3.7m
Sources: World Christian Database and US State Department reports on religious freedom
BBC News / Middle East