[17][18][30] Signed after the WW1, the Treaty of Lausanne explicitly guarantees the security and protection of both Greek and Armenian Orthodox Christian minorities.

[47] It was noted that the number of Eastern Orthodox Christians had risen sharply, mainly due to refugees from Russia and Ukraine.

[51] The historical region of Syria became one of the main centers of miaphisite Christianity, embodied in the Oriental Orthodoxy, which had accepted only the first three ecumenical councils: Nicaea (325), Constantinople (381) and Ephesus (431).

[57] The city was the home of the Ecumenical Patriarch of Constantinople and guardian of Christendom's holiest relics such as the Crown of thorns and the True Cross.

[59] Additionally, due to the decline of Rome and internal dissension in the other Eastern Patriarchates, the Church of Constantinople became, between the 6th and 11th centuries, the richest and most influential centre of Christendom.

Antioch was also the place where the followers of Jesus were called "Christians" for the first time in history, as well as being the site of one of the earliest and oldest surviving churches, established by Saint Peter himself.

[61] In accordance with the traditional custom of the time, the Ottoman sultan Mehmed II allowed his troops and his entourage three full days of unbridled pillage and looting in the Christian city of Constantinople, capital of the Roman Empire since its foundation by the Roman Emperor Constantine the Great in the 4th century AD, shortly after it was captured in 1453.

[64][62] The cathedral of Hagia Sophia was not exempted from the pillage and looting and specifically became its focal point, as the Ottoman Turks believed it to contain the greatest treasures and valuables of the city.

[65] Shortly after the defence of the Walls of Constantinople, the city collapsed and the Ottoman troops entered victoriously; the pillagers and looters made their way to the Hagia Sophia and battered down its doors before storming in.

[65] While most of the elderly, the infirm/wounded, and sick were killed, and the remainder (mainly teenage males and young boys) were chained up and sold into slavery.

[74] The Ottoman Empire was then at the height its power, and the French king Francis I had shortly before sustained a disastrous defeat at the Battle of Pavia.

[75] Kurds saw the Assyrians as dangerous foreigners and enforcers of the British colonizers, which made it justifiable to them to commit ethnic cleansing.

The Kurds fought the Assyrians also due to fears that the Armenians, or European colonial powers backing them, would assume control in Anatolia.

[3][77][78][79] Into the 19th century, the Christians of Istanbul tended to be either Greek Orthodox, members of the Armenian Apostolic Church or Catholic Levantines.

[84][85][86][87] The Greek forces who occupied Smyrna in the post-war period were defeated in the Turkish War of Independence which ended with the signing of the Treaty of Lausanne.

Other terms of the treaty included various provisions to protect the rights of religious minorities and a concession by the Turks to allow the Greek Orthodox Patriarchate to remain in Istanbul.

[90] In the pre-war period, Protestant Christian missionaries from North America had been actively involved in the Ottoman education system.

A 2004 report by the Turkish Armed Forces (TAF) similarly recommended implementing new laws to curb Christian missionary activities in the country.

[92] Since Turkish nationality was often perceived exclusively as a Muslim identity after the Balkan Wars, the influence of Protestant Christian missionaries on Turkey's Alevi population has been a concern since the era of Committee of Union and Progress rule.

[94] Historically, the Christian population of Turkey has been largely peaceful and non-disruptive, with the notable exception of one former Muslim convert to Christianity who hijacked the Turkish Airlines Flight 1476 in 2006 with the stated intent of flying it to the Vatican to meet the Pope and ask for his help to avoid serving in the Turkish Armed Forces, which he referred to as a "Muslim army".

[95] In 2013, the Washington Post reported that members of the ruling Justice and Development Party had expressed their desires to convert Hagia Sophia into a mosque.

Hagia Sophia, which is called ayasofya in Turkish, is an ancient Christian church dating to 360 AD that was converted into a mosque after Mehmed II invaded Constantinople in 1453.

[3] This includes the Istanbul pogrom of 1955, where non-Muslims were attacked and killed, as well as more recent attacks, such as the assassination of prominent Turkish–Armenian journalist Hrant Dink in 2007, the torture and murder of one German Protestant and two Turkish converts to Christianity in what Turkish media dubbed "the missionary massacres" in the same year,[108][109] and the killings of Italian Catholic priests, including Andrea Santoro, in 2006 and 2007.

In January 2024, two gunmen fatally shot a man during a church service in Istanbul in an attack claimed by the Islamic State (Daesh).

The Ecumenical Patriarch of Constantinople, Bartholomew I, for example, has a good relationship with the Focolare Movement and the new Apostolic Vicar of Istanbul, Bishop Massimiliano Palinuro.

[125] In 1924, Karahisarithis started to conduct the Christian liturgy in Turkish, and quickly won support from the establishment of the modern Republic of Turkey, formed after the defeat and dissolution of the Ottoman Empire (1908–1922).

[131] In addition to the Hours of the Office, the Byzantine Rite is used for the administration of sacraments; among these are Holy Communion (the most direct connection), baptism, Chrismation, confession, unction, matrimony, and ordination, as well as blessings, exorcisms, and other occasions.

Since the 12th century, the patriarchal seat itself was transferred to Mor Hananyo Monastery (Deir al-Za`faran), in southeastern Anatolia near Mardin (modern Turkey), where it remained until 1924.

Originally, one of its main centers was in the region of Hakkari, in the village of Qodchanis, that was the seat of Shimun-line patriarchs from the 17th century up to the advent of modern times.

[141] The Armenian Evangelical Church was founded in 1846, after Patriarch Matteos Chouhajian excommunicated members of the "Pietisical Union" who had started to raise questions about a possible conflicts between the Biblical scriptures and Sacred traditions.