Nestorianism is a term used inChristian theology andChurch history to refer to several mutually related butdoctrinarily distinct sets of teachings.^[1] The first meaning of the term is related to the original teachings of Christian theologianNestorius (d. c. AD 450), who promoted specific doctrines in the fields ofChristology andMariology. The second meaning of the term is much wider, and relates to a set of later theological teachings, that were traditionally labeled as Nestorian, but differ from the teachings of Nestorius in origin, scope and terminology.^[2] TheOxford English Dictionary defines Nestorianism as:

"The doctrine of Nestorius,Patriarch of Constantinople (appointed in 428), by which Christ is asserted to have had distinct human and divine persons."^[3]

Original Nestorianism is attested primarily by works of Nestorius, and also by other theological and historical sources that are related to his teachings in the fields ofMariology andChristology. His theology was influenced by teachings ofTheodore of Mopsuestia (d. 428), the most prominent theologian of theAntiochian School. Nestorian Mariology prefers the title Christotokos, which encompasses the termTheotokos ('God-bearer') forMary, thus emphasizing distinction between divine and human aspects of theIncarnation. Nestorian Christology promotes the concept of aprosopic union of two concrete realities (divine and human) inJesus Christ,^[4] thus trying to avoid and replace the concept of ahypostatic union of two natures. The distinction is between 'two hypostases in one person' and 'two natures in one person'. Hypostasis is not seen as subject, but rather a nature existing in reality. This Christological position is viewed by the West asradical dyophysitism,^[5] and differs from eastern orthodoxdyophysitism, that was reaffirmed at theCouncil of Chalcedon (451).^[6] Such teachings brought Nestorius into conflict with other prominent church leaders, most notablyCyril of Alexandria, who issued 12anathemas against him (430). Nestorius and his teachings were eventually condemned asheretical at theCouncil of Ephesus in 431, and again at theCouncil of Chalcedon in 451. His teachings were considered as heretical not only inChalcedonian Christianity, but even more inOriental Orthodoxy.^[6] The already long extantAssyrian Church of the East, would affirm the orthodoxy of Nestorius, lining up the tradition of the fathers which preceded him.

After the condemnation, some supporters of Nestorius, who were followers of theAntiochian School and theSchool of Edessa, relocated to theSasanian Empire, where they were affiliated with the localAssyrian community of the satrapy ofAsuristan (Assyria), many who were followers of theAssyrian Church, known as theChurch of the East, while others wereSyriac Orthodox. During the period from 484 to 612, gradual development led to the creation of specific doctrinal views within the Church of the East.^[7] Evolution of those views was finalized by prominentEast Syriac theologianBabai the Great (d. 628) who was using the specificSyriac termqnoma (ܩܢܘܡܐ) as a designation for dual (divine and human) substances within oneprosopon (person or hypostasis) of Christ. Such views were officially adopted by the Church of the East at a council held in 612.^[8]

Opponents of such views in the West inaccurately labeled them as "Nestorian", leading to the practice ofmislabeling theChurch of the East as Nestorian, and indeed theAssyrian people themselves as "Nestorians" .^[9] For a long time this seemed an appropriate usage, since Nestorius is officially venerated as asaint in the Assyrian Church of the East.^[10] But in modernreligious studies it has been criticized as wholly improper and misleading.^[11] As a consequence, both in scholarly literature and in the field ofinter-denominational relations, the termNestorian increasingly focuses on its primary meaning, the original teachings of Nestorius, rather than referring to the far older-originating Assyrian Church of the East or its offshoot, theChaldean Catholic Church.^[12]

Nestorianism was condemned asheresy at theCouncil of Ephesus (431). TheArmenian Church rejected theCouncil of Chalcedon (451) because they believedChalcedonian Definition was too similar to Nestorianism. ThePersian Nestorian Church, on the other hand, supported the spread of Nestorianism inPersarmenia. The Armenian Church and other eastern churches saw the rise of Nestorianism as a threat to the independence of their Church.Peter the Iberian, aGeorgian prince, also strongly opposed the Chalcedonian Creed.^[13] Thus, in 491, Catholicos Babken I of Armenia, along with theAlbanian andIberian bishops met inVagharshapat and issued a condemnation of the Chalcedonian Definition.^[14]

Nestorians held that the Council of Chalcedon proved theorthodoxy of their faith and had started persecuting non-Chalcedonian orMiaphysite Syriac Christians during the reign ofPeroz I. In response to pleas for assistance from theSyriac Church, Armenianprelates issued a letter addressed to Persian Christians reaffirming their condemnation of the Nestorianism as heresy.^[13]

Following the exodus toPersia, scholars expanded on the teachings of Nestorius and his mentors, particularly after the relocation of theSchool of Edessa to the (then) Persian city of Nisibis (modern-dayNusaybin inTurkey) in 489, where it became known as theSchool of Nisibis.^{[citation needed]} Nestorian monasteries propagating the teachings of the Nisibis school flourished in 6th century Persarmenia.^[13]

Despite this initial Eastern expansion, the Nestorians' missionary success was eventually deterred.David J. Bosch observes, "By the end of the fourteenth century, however, the Nestorian and other churches—which at one time had dotted the landscape of all of Central and even parts of East Asia—were all but wiped out. Isolated pockets of Christianity survived only in India. The religious victors on the vast Central Asian mission field of the Nestorians wereIslam andBuddhism".^[15]

Nestorianism is a radical form ofdyophysitism,^[5] differing from orthodox dyophysitism on several points, mainly by opposition to the concept ofhypostatic union. It can be seen as the antithesis toEutychian Monophysitism, which emerged in reaction to Nestorianism. Where Nestorianism holds that Christ had two loosely united natures, divine and human, Monophysitism holds that he had but a single nature, his human nature being absorbed into his divinity. A brief definition of NestorianChristology can be given as: "Jesus Christ, who is not identical with the Son but personally united with the Son, who lives in him, is onehypostasis and one nature: human."^[17] This contrasts with Nestorius' own teaching thatthe Word, which is eternal, and the Flesh, which is not, came together in a hypostatic union, 'Jesus Christ', Jesus thus being both fully man and God, of twoousia (Ancient Greek:οὐσία) (essences) but of oneprosopon (person).^[18] Both Nestorianism and Monophysitism were condemned as heretical at theCouncil of Chalcedon.

Nestorius developed his Christological views as an attempt to understand and explain rationally the incarnation of the divineLogos, the Second Person of the Holy Trinity as the man Jesus. He had studied at theSchool of Antioch where his mentor had beenTheodore of Mopsuestia; Theodore and other Antioch theologians had long taught aliteralist interpretation of the Bible and stressed the distinctiveness of the human and divine natures of Jesus. Nestorius took his Antiochene leanings with him when he was appointedPatriarch of Constantinople byByzantine emperorTheodosius II in 428.

Nestorius's teachings became the root of controversy when he publicly challenged the long-used titleTheotokos^[19] ('God-Bearer') for Mary. He suggested that the title denied Christ's full humanity, arguing instead that Jesus had two persons (dyoprosopism),^{[citation needed]} the divine Logos and the human Jesus. As a result of this prosopic duality, he proposedChristotokos ('Christ-Bearer') as a more suitable title for Mary.^[20]

He also advanced the image of Jesus as a warrior-king and rescuer ofIsrael over the traditional image of theChristus dolens.^[21]

Nestorius' opponents found his teaching too close to the heresy ofadoptionism – the idea that Christ had been born a man who had later been "adopted" as God's son. Nestorius was especially criticized byCyril,Patriarch of Alexandria, who argued that Nestorius's teachings undermined the unity of Christ's divine and human natures at theIncarnation. Some of Nestorius's opponents argued that he put too much emphasis on the human nature of Christ, and others debated that the difference that Nestorius implied between the human nature and the divine nature created a fracture in the singularity of Christ, thus creating two Christ figures.^[22] Nestorius himself always insisted that his views were orthodox, though they were deemedheretical at theCouncil of Ephesus in 431, leading to theNestorian Schism, when churches supportive of Nestorius and the rest of the Christian Church separated. However, this formulation was never adopted by all churches termed 'Nestorian'. Indeed, the modern Assyrian Church of the East, which reveres Nestorius, does not fully subscribe to Nestorian doctrine, though it does not employ the titleTheotokos.^[23]

Nestorianism became a distinct sect following theNestorian Schism, beginning in the 430s. Nestorius had come under fire from Western theologians, most notablyCyril of Alexandria. Cyril had both theological and political reasons for attacking Nestorius; on top of feeling that Nestorianism was an error against true belief, he also wanted to denigrate the head of a competing patriarchate.^{[citation needed]} Cyril and Nestorius askedPope Celestine I to weigh in on the matter. Celestine found that the titleTheotokos^[19] was orthodox, and authorized Cyril to ask Nestorius to recant. Cyril, however, used the opportunity to further attack Nestorius, who pleaded with Emperor Theodosius II to call a council so that all grievances could be aired.^[23]

In 431 Theodosius called the Council of Ephesus. However, the council ultimately sided with Cyril, who held that the Christ contained two natures in one divine person (hypostasis, unity of subsistence), and that the Virgin Mary, conceiving and bearing this divine person, is truly called the Mother of God (Theotokos). The council accused Nestorius ofheresy, and deposed him as patriarch.^[24] Upon returning to his monastery in 436, he was banished to Upper Egypt. Nestorianism was officially anathematized, a ruling reiterated at theCouncil of Chalcedon in 451. However, a number of churches, particularly those associated with theSchool of Edessa, supported Nestorius – though not necessarily his doctrine – and broke with the churches of the West. Many of Nestorius' supporters relocated to theSasanian Empire of Iran, home to a vibrant but persecuted Christian minority.^[25] In Upper Egypt, Nestorius wrote hisBook of Heraclides, responding to the two councils at Ephesus (431, 449).^[18]

(Not shown areante-Nicene,nontrinitarian, andrestorationist denominations.)

The western provinces of thePersian Empire had been home to Christian communities, headed by metropolitans, and later patriarchs ofSeleucia-Ctesiphon. The Christian minority in Persia was frequently persecuted by theZoroastrian majority, which accused local Christians of political leanings towards theRoman 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 ofTheodore of Mopsuestia and his followers, many of whom became dissidents after the Councils ofEphesus (431) andChalcedon (451). The Persian Church became increasingly opposed to doctrines promoted by those councils, thus furthering the divide betweenChalcedonian and Persian currents.^[6]

In 486, the MetropolitanBarsauma ofNisibis publicly accepted Nestorius' mentorTheodore of Mopsuestia as a spiritual authority. In 489, when theSchool of Edessa inMesopotamia was closed by Byzantine EmperorZeno for its pro-Nestorian teachings, the school relocated to its original home of Nisibis, becoming again theSchool of Nisibis, leading to the migration of a wave of Christian dissidents into Persia. The Persian patriarchBabai (497–502) reiterated and expanded upon the church's esteem forTheodore of Mopsuestia.

Now firmly established in Persia, with centers in Nisibis,Ctesiphon, andGundeshapur, and severalmetropoleis, 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 emperorKhosrow I; this ended in 545. The church survived these trials under the guidance of PatriarchAba I, who had converted to Christianity from Zoroastrianism.^[25]

The church emerged stronger after this period of ordeal, and increased missionary efforts farther afield. Missionaries established dioceses in theArabian Peninsula andIndia (theSaint Thomas Christians). They made some advances inEgypt, despite the strongMiaphysite presence there.^[26] Missionaries enteredCentral Asia and had significant success converting localTurkic tribes.

TheAnuradhapura Cross discovered in Sri Lanka strongly suggests a strong presence of Nestorian Christianity in Sri Lanka during the 6th century AD according toHumphrey 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).^[27][28][29]

Nestorian missionaries were firmly established in China during the early part of theTang dynasty (618–907); the Chinese source known as theNestorian Stele records a mission under a Persian proselyte namedAlopen as introducing Nestorian Christianity to China in 635. TheJingjiao Documents (also described by the Japanese scholar P. Y. Saeki as "Nestorian Documents") orJesus Sutras are said to be connected with Alopen.^[30]

Following theArab conquest of Persia, completed in 644, the Persian Church became adhimmi community under theRashidun 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.^[25] After that time, however, Nestorianism went into decline.^{[disputed –discuss]}

In a 1996 article published in theBulletin of the John Rylands Library,Fellow of the British AcademySebastian 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 'TheAssyrian Church of the East'. The Common Christological Declaration between the Catholic Church and the Assyrian Church of the East signed by PopeJohn Paul II and MarDinkha IV underlines the Chalcedonian Christological formulation as the expression of the common faith of these Churches and recognizes the legitimacy of the titleTheotokos."^[31]

In a 2017 paper,Mar Awa Royel, Bishop of theAssyrian 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."^[32]

Several historical records suggest that the Assyrian Church of the East may have been in Sri Lanka between the mid-5th and 6th centuries.^[27][28][29]

The accusations of Nestorianism have been used in contemporary theological discourse. One notable example is the case ofJohn MacArthur, as he has asserted that whenMary gave birth to Jesus, she did not give birth to God, but rather gave birth to Jesus in his humanity and that "it’s heretical to call the blood of Jesus Christ the blood of God."^[33][34] These statements have been critiqued as resembling Nestorianism by other Christians.^[35][36]

• Arianism
• Aramaic New Testament
• Hypostatic union
• Nestorian Evangelion
• Nestorianism and the church in India
• Christian influences in Islam

• "Unofficial Web Site of the 'Church of the East'". Nestorian.org.
• Lieu, Sam; Parry, Ken."Manichaean and (Nestorian) Christian Remains in Zayton (Quanzhou, South China)".Macquarie University. Archived fromthe original on July 19, 2008. RetrievedJanuary 24, 2010.
• Dickens, Mark (1999)."The Church of the East". Oxus Communications. Archived fromthe original on May 14, 2011. RetrievedFebruary 6, 2010.
• "Nestorius and Nestorianism".The Catholic Encyclopedia.