Theodore of Mopsuestia in the context of "Nestorianism"

The Second Council of Constantinople is the fifth of the first seven ecumenical councils recognized by both the Eastern Orthodox Church and the Catholic Church. It is also recognized by the Old Catholics and others. Protestant opinions and recognition of it are varied. Some Protestants, such as Calvinists, recognize the first four councils, whereas Lutherans and most Anglo-Catholics accept all seven. Constantinople II was convoked by the Byzantine Emperor Justinian I under the presidency of Patriarch Eutychius of Constantinople. It was held from 5 May to 2 June 553. Participants were overwhelmingly Eastern bishops—only sixteen Western bishops were present, including nine from Illyricum and seven from Africa, but none from Italy—out of the 152 total.

The main work of the council was to confirm the condemnation issued by edict in 551 by the Emperor Justinian against the Three Chapters. These were the Christological writings and ultimately the person of Theodore of Mopsuestia (died 428), certain writings against Cyril of Alexandria's Twelve Anathemas accepted at the Council of Ephesus, written by Theodoret of Cyrrhus (died c. 466), and a letter written against Cyrillianism and the Ephesian Council by Ibas of Edessa (died 457).

Metropolitanate of India (Syriac: Beth Hindaye) was an East Syriac ecclesiastical province of the Church of the East, at least nominally, from the seventh to the sixteenth century. The Malabar region (Kerala) of India had long been home to a thriving Eastern Christian community, known as the Saint Thomas Christians. The community traces its origins to the evangelical activity of Thomas the Apostle in the 1st century. The Christian communities in India used the East Syriac Rite, the traditional liturgical rite of the Church of the East. They also adopted some aspects of Dyophysitism of Theodore of Mopsuestia, often inaccurately referred as Nestorianism, in accordance with theology of the Church of the East. It is unclear when the relation between Saint Thomas Christian and the Church of the East was established. Initially, they belonged to the metropolitan province of Fars, but were detached from that province in the 7th century, and again in the 8th, and given their own metropolitan bishop.

Due to the distance between India and the seat of the Patriarch of the Church of the East, communication with the church's heartland was often spotty, and the province was frequently without a bishop. An eleventh-century reference states that the metropolitan province of India had been 'suppressed', due to communication difficulties. At the beginning of the fourteenth century the Indian Church was again dependent on the Church of the East. Although India was supplied with bishops from the Middle East, the effective control lay in the hands of an indigenous priest known as Arkkadiyakkon or Archdeacon. He was the community leader of Saint Thomas Christians. Even in times when there were multiple foreign bishops, there was only one archdeacon for entire Saint Thomas Community. As such, the Indian church was largely autonomous in operation, though the authority of the Patriarch was always respected.

The Three-Chapter Controversy, a phase in the Chalcedonian controversy, was an attempt to reconcile the non-Chalcedonians of Syria and Egypt with Chalcedonian Christianity, following the failure of the Henotikon. The Three Chapters (τρία κεφάλαια, tría kephálaia) that Emperor Justinian I anathematized were:

1. The person and writings of Theodore of Mopsuestia
2. Certain writings of Theodoret of Cyrus
3. The letter of Ibas of Edessa to Maris

The School of Edessa (Syriac: ܐܣܟܘܠܐ ܕܐܘܪܗܝ) was a Christian theological school of great importance to the Syriac-speaking world. It had been founded as long ago as the 2nd century by the kings of the Abgar dynasty. In 363, Nisibis fell to the Persians, causing St. Ephrem the Syrian, accompanied by a number of teachers, to leave the School of Nisibis. They went to Edessa, where Ephrem took over the directorship of its school. Then, its importance grew still further. There were innumerable monasteries at Edessa housing many monks. Ephrem occupied a cell there, practicing the ascetic life, interpreting Holy Scripture, composing poetry and hymns and teaching in the school, as well as instructing young girls in church music.

The first recorded director of the School of Edessa was Qiiore, in the early 5th century. He had ascetic and scholarly qualifications and an administrative ability. Occupying the Chair of Exegesis (mepasqana), he replaced the texts of Ephraim with those of Theodore of Mopsuestia. With that seminal decision, Qiiore embarked upon a course of study that was to mix the deductive principles of Aristotle with Theodore's Dyophysite creed.

Aba I (or, with his Syriac honorific, Mar Aba I) or Mar Abba the Great was the Patriarch of the Church of the East at Seleucia-Ctesiphon from 540 to 552. He introduced to the church the anaphoras of Theodore of Mopsuestia and Nestorius beside the more ancient liturgical rite of Addai and Mari. Though his tenure as catholicos saw Christians in the region threatened during the Persian-Roman wars and attempts by both Sassanid Persian and Byzantine rulers to interfere with the governance of the church, his reign is reckoned a period of consolidation, and a synod he held in 544 as (despite excluding the Diocese of Merv) instrumental in unifying and strengthening the church. In 544, the Synod of Mar Aba I adopted the ordinances of the Council of Chalcedon. He is thought to have written and translated a number of religious works. After his death in February 552, the faithful carried his casket from his simple home across the Tigris to the monastery of Mar Pithyon.

Aba is a highly regarded and significantly venerated saint in the Assyrian Church of the East, the Ancient Church of the East, and the Chaldean Catholic Church. He is documented in the Ausgewählte Akten Persischer Märtyrer, and The Lesser Eastern Churches, two biographies of Eastern saints. The first seminary of the Chaldean Catholic Church outside of Iraq was established in July 2008 in El Cajon, San Diego, as the Seminary of Mar Abba the Great.

The Catechetical School of Antioch was one of the two major Christian centers of the study of biblical exegesis and theology during Late Antiquity; the other was the School of Alexandria. This group was known by this name because the advocates of this tradition were based in the city of Antioch in Roman Syria (modern-day Turkey), one of the major cities of the ancient Roman Empire. Although there were early interpreters from Antioch, like Theophilus of Antioch, the proper school of exegesis at Antioch belongs to the period of the 4th and 5th centuries.

While the Christian intellectuals of Alexandria emphasized the allegorical interpretation of Scriptures and tended toward a Christology that emphasized the union of the human and the divine, those in Antioch held to a more literal and occasionally typological exegesis and a Christology that emphasized the distinction between the human and the divine in the person of Jesus Christ. They rejected notions of instantaneous creation held by other figures such as Augustine, and instead literally held to the notion of the progressive creation of the Genesis creation narrative: those things created on the sixth day did not exist in the fifth, that made on the fifth day did not exist in the fourth, and so on. Advocates included Acacius of Caesarea, Severian of Gabala, Theodore of Mopsuestia, Theodoret, and others.