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 and violence.
Lebanon is the only Middle Eastern country where Christians were once dominant and retain considerable political power.
The country fought a civil war from 1975-1989 largely along religious lines, and relations between the patchwork of Lebanon's religious communities remain delicate.
The last official census was conducted 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, tensions 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.
About 20.5% 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, practising their religion and trying to maintain their identity as part of an overwhelmingly Muslim population group.
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 for the Jewish people.
There is freedom of worship in Israel and proselytising is allowed.
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.
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 inhabitants.
The two largest Churches are Greek Orthodox and Catholic, 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.
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.
The Coptic language - a derivative of the ancient Egyptian language, written mainly in the Greek alphabet - is still used for small parts of services.
Christian-Muslim relations have deteriorated in recent years, with outbreaks of violence by radical Islamists against Christians and their places of worship.
Egyptian Christians have accused the post-Mubarak governing military council of being too lenient on the perpetrators of the attacks.
Copts also complain of discrimination, including a law requiring presidential permission for churches to be built.
A plethora of other Catholic, Orthodox, Protestant and Armenian Churches are present in smaller numbers in Egypt.
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.
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 - which has 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. There are also Syrian Orthodox, Syrian Catholic, Armenian Orthodox, Armenian Catholic, Assyrian and Chaldean (see Iran and Iraq) Christians.
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.
There is generally freedom of religion, apart 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 in Jordan are largely amicable.
There has been a Christian presence in what is now Iraq since the 2nd Century. The largest groups are the Chaldean and Assyrian Churches.
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 derivative 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 after the US-led invasion in 2003 led to up to half the Christian population leaving, although there are no official statistics.
In November 2010, 52 people were killed as security forces stormed a Catholic church in Baghdad to free dozens of people held hostage. A Sunni militant group claimed responsibility for the attack, the deadliest such incident suffered by Iraq's Christians in modern times.
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.
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.
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.
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 expressions of non-Muslim religion are banned.
Private religious gatherings are also prohibited, although the ban is only enforced intermittently.