Nestorianism

Nestorianism is a Christological doctrine formulated by the Mesopotamian priest, and patriarch of Constantinople, Nestorius. Nestorianism was deemed heretical by church authorities in the western world but found significant following and acceptance among the Iranian and Altaic peoples of Central Asia. Nestorianism would go on to flourish in East Asia, becoming the state religion under the Naimans of Korea, the Myojo Dynasty of Japan, and the Zhao/Qiang Tangut Dynasties.

Nestorian Christianity is closely associated with the Church of the East (found among the Assyrians of Mesopotamia, the Minyaks of Southeast Asia, and the indigenous Christian minority of China), as well as the Korean Orthodox Church and Japanese Orthodox Church. Nestorianism is the second largest denomination of Christianity worldwide, falling just behind Roman Catholicism, while still significantly ahead of Protestant Christianity.

History
Nestorianism arose in the 5th Century out of the understanding of the former Patriarch of Constantinople, Nestorius. Nestorian Christology was deemed heretical at the Council of Chalcedon but flourished among the Christians of Mesopotamia. Nestorian Christianity was widely successful among the Indo-Iranian peoples of Central Asia, who took it to the Chinese and the westernmost Mongolic peoples.

When the Neo-Heilong Empire arose in Central Asia and expanded East into China, the Christian communities in Central Asia were displaced, with Christianity largely disappearing in the area, with Christians being pushed southwest and northeast. Nestorian Christianity thus spread rapidly into East Asia, with Iranian Christians migrating into China seeking refuge. However, most significantly, the Naiman Mongols, a recently converted people, and the nearby Khitans were displaced, with the Naimans and their subordinate Khitans moving east as they escaped the Neo-Heilongs, conquering the Korean Peninsula. The so-called "Red Khitans" moved south into China, establishing their own state of Liao. The Liao destroyed the Tuyuhun Confederation, displacing the Tanguts, who passed into the southwest of China, who were later Christianized by a mixture of Liao and Sino-Syriac missionaries.

The Naimans established a dynasty over the Koreans and quickly set about patronizing Nestorian Christianity among the peoples of the Korean Peninsula. Korea became a center of philosophy and theology in East Asia, attracting Christians from China and Liao to migrate to Korea to study in the Korean monasteries.

The Naimans later began to send missionaries to Japan, attracting some support among clans in Southern Honshu and Kyushu.

As Christianity grew and flourished in Japan, the Tanguts managed to wage a war against the Song Dynasty of China, in which they conquered the whole of China, establishing the Qiang Dynasty. The Tanguts attempted to promote better relations with the Koreans, but the Tangut dynasty of China was constantly plagued by insurgency carried out by the Han Chinese, who were loathe to be subservient to a dynasty of foreigners.

The Japanese were soon to establish the Myojo dynasty, who overthrew the Yamato Dynasty and established a Nestorian authority over the country.

The creation of the Myojo began a tradition of philosophical exchange between Japan and Korea. The Japanese established a doctrine of Divine Right, based on the Chinese concept of the Mandate of Heaven and their own ideas of a divine emperor. The idea of Divine Kingship became established among the Japanese and the Koreans but never was substantial among the Tanguts.

The Qiangs were overthrown by the Tang dynasty, who rejected Christianity as a state ideology, advancing rulership based on a new form of Confucianism (Neo-Confucianism) that was largely secular and legalistic.

However, the tolerance of Christians in China would come to a violent end after the last remnants of the Heilongs staged one final assault, which prompted the collapse of the Tang, and the ascension of the Mingjun as a provisional government, who gave Christians in their administered territories the options of conversion to Manichaeism or death. This reached a national level when the Ming Dynasty was established nationally when anti-Christian legislation was applied, and the Christian communities were targeted for extermination. Widespread emigration from China followed, with most choosing to go to Korea when possible, while other Tanguts escaped south, moving into the Burmese states, but being so distinct from their new neighbors that they never fully assimilated into the Burmese society, eventually evolving into the people called the Minyaks. The Minyaks were able to maintain the Syriac language in their services, something that set them apart from their neighbors further, preserving their unique identity while the Tangut language slowly died out among them. Modern Minyak dialects of Burmese show significant substrate and loanwords from Tangut and Syriac, that sets it apart from those of the Buddhist Bamars.

Later, Europeans would come in contact with the indigenous Christians of Asia, and decide to convert them to Catholicism to better manipulate their loyalties. While the Koreans were quick to shut down Portuguese missionary activity in their borders, the decentralized Japanese were more receptive, with the south of the country converting rapidly to Portuguese-style Roman Catholicism.

However, Korea was not spared of turmoil in this time, as the Europeans brought the ideas of the Protestant Reformation, which caused the establishment of a Korean Reformation in Korea, which the kingdom attempted to suppress, leading to the Wars of Reformation.

Nestorianism later was brought to the forefront of world politics again when sectarian violence broke out in Japan in the 1960s, leading to a mass immigration of Japanese refugees to the Americas, Korea, and Europe.

Core Tenants
Nestorian Christianity is a Christological doctrine based on the idea of Jesus possessing two distinct natures. One human nature, and one divine nature, that were within the same person. Nestorians had formulated that the divine nature of Jesus was created by God as the Logos, while his human self was born from his human mother. Nestorianism was denounced as heresy by mainstream western Christianity but flourished in the East. As a result of their understanding of Jesus' nature, they believed that during his time in leading his ministry, Jesus' divine self, the Logos, overpowered his human self, essentially fronting over his human personality.

Nestorians also refused to acknowledge Mary as the 'Mother of God', and many contended that the Human Jesus was not the "son" of God, while the Logos was the true son.

Korean Nestorianism
The first major center of Christian theology in East Asia was Korea. The city of Pyongyang had become known for being a sort of pet project for the Naimans in patronizing Christianity in their lands. The doctrine that was established in Korea had become definitive for all forms of East Asian Nestorianism.

The Korean doctrine was established by the legendary theologian Sung Markwe-Yo, known to Westerners under the Latinized names of Josonus Paraquinas. Sung established the basic tenants of the two persons in Jesus Christ being not just distinct natures but wholly different people, and the idea of salvation being only accessible through faith within him, rather than by individual good works. Sung postulated that the human Jesus Christ was sacrified by God as a sacrifical lamb to atone for all of humanity's sins, while the Logos would return to heaven, and return on the Day of Judgement. Sung was so influential that some Korean theologians later stated that "the words of Sung Markwe-Yo are synonymous with Nestorianism."

Japanese Nestorianism
Japanese Nestorianism diverged significantly from Korean Nestorianism. Osaka became a major center of Christian Scholarship, and it was here that the ideas fundamental to the Japanese take on Christianity developed. Japanese Christians posited that like Mary was the early mother of Jesus, so too did the Logos have a divine mother in heaven. Thus, the Japanese introduced the idea of two Marys existing, one in heaven and one on Earth. The Japanese also believed that their ancestors exist in a state of limbo where they can intercede with God on the behalf of their descendants, leading to the acceptance and integration of ancestor veneration into their strain of Christianity. The Japanese also integrated their prexisting roles into their new church, with a specialized female prestial role, who acts as a second head of the chruch. As well, the role of Mikos was maintained in the Japanese strain, becoming a group of young caretakers for the churches who also carry out basic tasks at masses, such as lighting candles and insense, as well as leading the opening processions and carrying the cross at said processions.

Defining Characteristics of Koreano-Japonic Orthodoxy vs the Church of the East
Perhaps the most immediate difference is the fact that the Koreano-Japonic Churches use their local vernaculars in scholarship and worship, while those communities who are in communion with the Church of the East maintain the use of Syraic in their services and scholarship.

As well, the Church of the East still asserts the authority of the Patriarch of the East, while Koreano-Japonic denominations do not, and largely promote the idea of autocephaly, and believe that they should self govern rather than answer directly to the Patriarch.