India (East Syriac ecclesiastical province) in the context of "Dyophysitism"

The Syriac language (/ˈsɪriæk/ SIRR-ee-ak; Classical Syriac: ܠܫܢܐ ܣܘܪܝܝܐ, romanized: Leššānā Suryāyā), also known natively in its spoken form in early Syriac literature as Edessan (Urhāyā), the Mesopotamian language (Nahrāyā) and Aramaic (Aramāyā), is an Eastern Middle Aramaic dialect. Classical Syriac is the academic term used to refer to the dialect's literary usage and standardization, distinguishing it from other Aramaic dialects also known as 'Syriac' or 'Syrian'. In its West-Syriac tradition, Classical Syriac is often known as leššōnō kṯoḇonōyō (lit. 'the written language or the book language') or simply kṯoḇonōyō, or kṯowonōyō, while in its East-Syriac tradition, it is known as leššānā ʔatīqā (lit. 'the old language') or saprāyā (lit. 'scribal or literary').

It emerged during the first century AD from a local Eastern Aramaic dialect that was spoken in the ancient region of Osroene, centered in the city of Edessa. During the Early Christian period, it became the main literary language of various Aramaic-speaking Christian communities in the historical region of Ancient Syria and throughout the Near East. As a liturgical language of Syriac Christianity, it gained a prominent role among Eastern Christian communities that used both Eastern Syriac and Western Syriac rites. Following the spread of Syriac Christianity, it also became a liturgical language of eastern Christian communities as far as India and China. It flourished from the 4th to the 8th century, and continued to have an important role during the next centuries, but by the end of the Middle Ages it was gradually reduced to liturgical use, since the role of vernacular language among its native speakers was overtaken by several emerging Neo-Aramaic languages.

The Saint Thomas Christians, also called Syrian Christians of India, Marthoma Suriyani Nasrani, Malankara Nasrani, or Nasrani Mappila, are an ethno-religious community of Indian Christians in the state of Kerala (Malabar region), who, for the most part, employ the Eastern and Western liturgical rites of Syriac Christianity. They trace their origins to the evangelistic activity of Thomas the Apostle in the 1st century. The Saint Thomas Christians had been historically a part of the hierarchy of the Church of the East but are now divided into several different Eastern Catholic, Oriental Orthodox, Protestant, and independent bodies, each with their own liturgies and traditions. They are based in Kerala and they speak Malayalam. Nasrani or Nazarene is a Syriac term for Christians, who were among the first converts to Christianity in the Near East.

Historically, this community was organised as the Province of India of the Church of the East, by Patriarch Timothy I (780–823 AD) in the eighth century, it was served by bishops and a local dynastic archdeacon. In the 14th century, the Church of the East declined in the Near East, due to persecution from Tamerlane. Portuguese colonial overtures to bring St Thomas Christians into the Latin Church of the Catholic Church, administered by their Padroado system in the 16th century, led to the first of several rifts (schisms) in the community. The attempts of the Portuguese culminated in the Synod of Diamper, formally subjugating them to the Portuguese Padroado and imposing upon them the Roman Rite of worship. The Portuguese oppression provoked a violent resistance among the Thomasine Christians, that took expression in the Coonan Cross Oath protest in 1653. This led to the permanent schism among the Thomas' Christians of India, leading to the formation of Puthankoor or Puthankūttukār ("New allegiance" ) and Paḻayakūṟ or Pazhayakūr ("Old allegiance") factions. The Paḻayakūṟ comprise the present day Syro-Malabar Church and Chaldean Syrian Church which continue to employ the original East Syriac Rite. The Puthankoottukar, who continued to resist the Catholic missionaries, organized themselves as the independent Malankara Church and entered into a new communion with the Syriac Orthodox Church of Antioch, inheriting from them the West Syriac Rite, replacing the old East Syriac Rite liturgy.

Thoma Darmo (21 September 1904 – 7 September 1969) was the Catholicos-Patriarch of the Ancient Church of the East, from 1968 to 1969. Prior to that, he served as Metropolitan of India, from 1952 to 1964, within the Church of the East.