Nestorianism

== Church of the East ==
{{main|Church of the East}}{{See also|Ancient Christianity in the Indian Subcontinent}}
{{multiple image|align=right|total_width=330
|image1=Da Qin Pagoda.jpg||caption1=The [[Daqin Pagoda]], controversially claimed to be part of an early [[Church of the East in China|Nestorian church]] in what was then [[Chang'an]], now [[Xi'an]], China, built during the [[Tang dynasty]] (AD 618–907)
|image2=Entry of Jesus Christ into Jerusalem, with a Female Figure in T'ang Costume, Chotscho, Sinkiang.jpg|caption2=[[Murals from the Christian temple at Qocho|Entry of Jesus Christ into Jerusalem]], with a female figure dressed in a [[Women's clothing in China|Tang dynasty costume]], AD 683–770.
}}
[[File:Yuan stone Nestorian inscription (rep).JPG|thumb|right|Chinese stone inscription of a [[Nestorian Cross]] from a monastery of [[Fangshan District]] in [[Beijing]] (then called Dadu, or [[Khanbaliq]]), dated to the [[Yuan Dynasty]] (AD 1271–1368) of medieval China.]]
[[File:An epitaph of a Nestorian Christian.jpg|thumb|right|Epitaph of a Nestorian, unearthed at [[Chifeng]], [[Inner Mongolia]]]]

The western provinces of the [[Sasanian Empire|Persian Empire]] had been home to Christian communities, headed by metropolitans, and later patriarchs of [[Seleucia-Ctesiphon]]. The Christian minority in Persia was frequently persecuted by the [[Zoroastrianism|Zoroastrian]] majority, which accused local Christians of political leanings towards the [[Roman Empire]]. In 424, the Church in Persia declared itself independent, in order to ward off allegations of any foreign allegiance. By the end of the 5th century, the Persian Church increasingly aligned itself with the teachings of [[Theodore of Mopsuestia]] and his followers, many of whom became dissidents after the Councils of [[Council of Ephesus (431)|Ephesus]] (431) and [[Council of Chalcedon|Chalcedon]] (451). The Persian Church became increasingly opposed to doctrines promoted by those councils, thus furthering the divide between [[Chalcedonian Christianity|Chalcedonian]] and Persian currents.{{sfn|Meyendorff|1989|p=}}

In 486, the Metropolitan [[Barsauma of Nisibis|Barsauma]] of [[Nisibis]] publicly accepted Nestorius' mentor [[Theodore of Mopsuestia]] as a spiritual authority. In 489, when the [[School of Edessa]] in [[Mesopotamia]] was closed by Byzantine Emperor [[Zeno (emperor)|Zeno]] for its pro-Nestorian teachings, the school relocated to its original home of Nisibis, becoming again the [[School of Nisibis]], leading to the migration of a wave of Christian dissidents into Persia. The Persian patriarch [[Babai (Nestorian patriarch)|Babai]] (497–502) reiterated and expanded upon the church's esteem for [[Theodore of Mopsuestia]].

Now firmly established in Persia, with centers in Nisibis, [[Ctesiphon]], and [[Gundeshapur]], and several [[Metropolis (religious jurisdiction)|''metropoleis'']], the Persian Church began to branch out beyond the Sasanian Empire. However, through the sixth century, the church was frequently beset with internal strife and persecution by Zoroastrians. The infighting led to a schism, which lasted from 521 until around 539 when the issues were resolved. However, immediately afterward Roman-Persian conflict led to the persecution of the church by the Sassanid emperor [[Khosrow I]]; this ended in 545. The church survived these trials under the guidance of Patriarch [[Aba I]], who had converted to Christianity from Zoroastrianism.<ref name=Britannica/>

The church emerged stronger after this period of ordeal, and increased missionary efforts farther afield. Missionaries established dioceses in the [[Arabian Peninsula]] and [[India]] (the [[Saint Thomas Christians]]). They made some advances in [[Egypt]], despite the strong [[Miaphysitism|Miaphysite]] presence there.<ref>{{cite book |last=Campbell |first=Ted |title=Christian Confessions: A Historical Introduction |url=https://books.google.com/books?id=p2mUxxxGt_sC&pg=PA62 |year=1996 |location=Westminster |publisher=[[John Knox Press]] |isbn=978-0-664-25650-0 |page=62 |via=[[Google Books]]}}</ref> Missionaries entered [[Central Asia]] and had significant success converting local [[Turkic peoples|Turkic]] tribes.

The [[Anuradhapura cross|Anuradhapura Cross]] discovered in Sri Lanka strongly suggests a strong presence of Nestorian Christianity in Sri Lanka during the 6th century AD according to [[H. W. Codrington|Humphrey Codrington]], who based his claim on a 6th-century manuscript, [[Christian Topography]], that mentions of a community of Persian Christians who were known to reside in Taprobanê (the Ancient Greek name for Sri Lanka).<ref name="Assyrian Church News">{{cite news |title=Mar Aprem Metropolitan Visits Ancient Anuradhapura Cross in Official Trip to Sri Lanka |url=http://news.assyrianchurch.org/2013/08/06/mar-aprem-metropolitan-visits-ancient-anuradhapura-cross-in-official-trip-to-sri-lanka/4480 |access-date=6 August 2013 |publisher=Assyrian Church News |archive-url=https://web.archive.org/web/20150226144609/http://news.assyrianchurch.org/2013/08/06/mar-aprem-metropolitan-visits-ancient-anuradhapura-cross-in-official-trip-to-sri-lanka/4480 |archive-date=2015-02-26}}</ref><ref name="Sunday Times">{{cite news |last1=Weerakoon |first1=Rajitha |title=Did Christianity exist in ancient Sri Lanka? |url=https://www.sundaytimes.lk/110626/Plus/plus_07.html |access-date=2 August 2021 |publisher=Sunday Times |date=June 26, 2011}}</ref><ref name="Main interest">{{cite news |title=Main interest |url=http://www.highbeam.com/doc/1P3-2326613141.htmlhttps://web.archive.org/web/20150329194052/http://www.highbeam.com/doc/1P3-2326613141.html |access-date=2 August 2021 |work=Daily News |date=22 April 2011|archive-url=https://web.archive.org/web/20150329194052/http://www.highbeam.com/doc/1P3-2326613141.htmlhttps://web.archive.org/web/20150329194052/http://www.highbeam.com/doc/1P3-2326613141.html |archive-date=2015-03-29}}</ref>

Nestorian missionaries were firmly established in China during the early part of the [[Tang dynasty]] (618–907); the Chinese source known as the [[Nestorian Stele]] records a mission under a Persian proselyte named [[Alopen]] as introducing Nestorian Christianity to China in 635. The [[Jingjiao Documents]] (also described by the Japanese scholar P. Y. Saeki as "Nestorian Documents") or [[Jesus Sutras]] are said to be connected with Alopen.<ref>{{cite book |last1=Riegert |first1=Ray |title=The Lost Sutras of Jesus: Unlocking the Ancient Wisdom of the Xian Monks |date=January 26, 2006 |publisher=Ulysses Press |isbn=1-56975-522-1 |pages=9–23 |url=https://books.google.com/books?id=rDuNAAAAMAAJ&q=the+lost+sutras+of+jesus |via=[[Google Books]]}}</ref>

Following the [[Muslim conquest of Persia|Arab conquest of Persia]], completed in 644, the Persian Church became a {{transliteration|ar|[[dhimmi]]}} community under the [[Rashidun Caliphate]]. The church and its communities abroad grew larger under the caliphate. By the 10th century it had 15 metropolitan sees within the caliphate's territories, and another five elsewhere, including in China and India.<ref name=Britannica/> After that time, however, Nestorianism went into decline.{{Disputed inline|date=October 2019}}

=== Assyrian Church of the East ===
[[File:Church of Saint Mary - Urmia - Iran - کلیسای ننه مریم، ارومیه - ایران.jpg|thumb|upright=0.9|[[St. Mary Church, Urmia|Saint Mary Church]]: an ancient [[Assyrian Church of the East|Assyrian]] church located in the city of [[Urmia]], [[West Azerbaijan Province]], [[Iran]].]]

In a 1996 article published in the ''[[Bulletin of the John Rylands Library]]'', [[Fellow of the British Academy]] [[Sebastian Brock]] wrote: "the term 'Nestorian Church' has become the standard designation for the ancient oriental church which in the past called itself 'The Church of the East', but which today prefers the fuller title 'The [[Assyrian Church of the East]]'. The Common Christological Declaration between the Catholic Church and the Assyrian Church of the East signed by Pope [[John Paul II]] and Mar [[Dinkha IV]] underlines the Chalcedonian Christological formulation as the expression of the common faith of these Churches and recognizes the legitimacy of the title ''Theotokos''."<ref>{{cite web |title=Common Christological Declaration between the Catholic Church and the Assyrian Church of the East |url=https://www.vatican.va/roman_curia/pontifical_councils/chrstuni/documents/rc_pc_chrstuni_doc_11111994_assyrian-church_en.html |access-date=8 February 2020}}</ref>

In a 2017 paper, [[Mar Awa Royel]], Bishop of the [[Assyrian Church of the East|Assyrian Church]], stated the position of that church: "After the Council of Ephesus (431), when Nestorius the patriarch of Constantinople was condemned for his views on the unity of the Godhead and the humanity in Christ, the Church of the East was branded as 'Nestorian' on account of its refusal to anathematize the patriarch."<ref>{{Cite web |url=https://bethkokheh.assyrianchurch.org/articles/855 |title=The Assyrian Church of the East: A Panoramic View of a Glorious History- Mar Awa Royel |date=2017-10-04 |website=Church of Beth Kokheh Journal |language=en-AU |access-date=2019-10-25}}</ref>

Several historical records suggest that the Assyrian Church of the East may have been in Sri Lanka between the mid-5th and 6th centuries.<ref name="Assyrian Church News"/><ref name="Sunday Times"/><ref name="Main interest"/>