History of Christianity

====Near East, Byzantium and schism====
[[File:Church of the East in the Middle Ages.svg|thumb|The [[Church of the East]] during the Middle Ages|alt=map showing Church of the East in the Middle Ages]]
[[File:Hagia Sophia in Istanbul (focused on the original Roman building).jpg|thumb|[[Hagia Sophia]] was the religious and spiritual centre of the [[Eastern Orthodox Church]] for nearly one thousand years. The [[Hagia Sophia]] and the [[Parthenon]] were converted into mosques. Violent persecutions of Christians were common and reached their climax in the [[Armenian genocide|Armenian]], [[Assyrian genocide|Assyrian]], and [[Greek genocide|Greek]] genocides.{{sfn|Barton|1998b|p=vii}}{{sfn|Morris|Ze'evi|2019|pp=3–5}}|alt=image of Hagia Sophia]]
Towards the end of the sixth century, two main kinds of Christian communities had formed in [[Syria]], [[Egypt]], [[Persia]], and [[Armenia]]: urban churches which upheld the [[Council of Chalcedon]] (451 CE) saying Christ had one human/divine nature, and Nestorian churches which came from the desert monasteries asserting Christ had two separate natures.{{sfn|Dorfmann-Lazarev|2008|pp=65-66}} The distinctive doctrinal and cultural identities of these churches played a decisive role in their history after the Arab conquest.{{sfn|Dorfmann-Lazarev|2008|pp=66-67}}

Intense missionary activity between the fifth and eighth centuries led to eastern [[Iran]], [[Arabia]], central [[Asia]], China, and the coasts of [[India]] and Indonesia adopting [[Nestorian Christianity]]. Syrian Nestorians had settled in the [[Persian Empire]] which spread over modern [[Iraq]], [[Iran]], and parts of Central Asia.{{sfn|Brown|2008|p=5}}{{sfn|Micheau|2006|p=378}} The rural areas of Upper Egypt were all Nestorian. [[Copts|Coptic]] missionaries spread the faith up the Nile to [[Nubia]], [[Eritrea]], and [[Ethiopia]].{{sfn|Dorfmann-Lazarev|2008|pp=66-67}}

From the early 600s, a series of Arab military campaigns conquered Syria, Mesopotamia, Egypt and Persia.{{sfn|Matthews|Platt|1992|pp=192, 199}}{{sfn|Barton|2009|p=xvii}} Conquest, conflict, and persecution exercised a lasting influence on the churches in these regions.{{sfn|Dorfmann-Lazarev|2008|p=85}} Under Islamic rule, persecution of non-Muslims was particularly devastating in cities where Chalcedonian churches were located. The monastic background of the Nestorians made their churches more remote, so they often escaped direct attention. In the following centuries, it was the Nestorian churches who were best able to survive and cultivate new traditions.{{sfn|Dorfmann-Lazarev|2008|p=66}}

[[Mozarabs|''Andalusi Christians'']],{{sfn|Bennison|2016|p=166}} from the [[Iberian Peninsula]] lived under [[Muslims|Muslim]] rule from [[Muslim conquest of Spain|711]] to [[Granada War|1492]].{{sfn|Fierro|2008|pp=137–164}} The martyrdoms of forty-eight Christians for defending their Christian faith took place in [[Emirate of Córdoba|Córdoba]] between 850 and 859.{{sfn|Graves|1964|p=644}}{{sfn|Sahner|2020|pp=1–28}}{{sfn|Fierro|2008|pp=137–164}}{{sfn|Trombley|1996|pp=581–582}} Executed under [[Abd al-Rahman II]] and [[Muhammad I of Córdoba|Muhammad I]], the record shows the executions were for capital violations of Islamic law, including [[Apostasy in Islam|apostasy]] and [[Islam and blasphemy|blasphemy]].{{sfn|Sahner|2020|pp=1–28}}{{sfn|Fierro|2008|pp=137–164}}{{sfn|Trombley|1996|pp=581–582}}

Many cultural, geographical, geopolitical, and linguistic differences between East and West existed. There were disagreements over whether Pope or Patriarch should lead the Church, whether mass should be conducted in Latin or Greek, whether priests must remain celibate, and other points of doctrine such as the ''[[Filioque|Filioque Clause]]'' and Nestorianism.{{sfn|Matthews|Platt|1992|p=185}}{{sfn|Meyendorff|1979|p=intro.}}{{sfn|Lorenzetti|2023}} Eventually, this produced the [[East–West Schism]], also known as the "Great Schism" of 1054, which separated the Church into Western Catholicism and Eastern Orthodoxy.{{sfn|Meyendorff|1979|p=intro.}}