Church of the East Christians in India were part of the
Church of the East up until the late 16th century. Following the
schism of 1552 in the Church of the East, when Monk
Yohannan Sulaqa and his followers joined the Catholic Church, forming the
Chaldean Catholic Church, both the traditional and the Chaldean Catholic factions sent bishops to India. The first of the Chaldean Catholic bishops in India was
Yawsep Sulaqa, the brother of Yohannan Sulaqa. Another bishop,
Abraham, arrived in India as a traditionalist bishop but later joined the Catholic faction.
Synod of Diamper and Coonan Cross Oath Abraham was to become the last Chaldean bishop to govern the undivided Saint Thomas Christian community. Following his death in 1597, the Portuguese missionaries, who had arrived along with the
colonial traders to India, started a vigorous and comprehensive process of
Latinisation in liturgy and discipline among the local Christians and prevented other East Syriac bishops from reaching Malabar. These efforts culminated in the so-called
Synod of Diamper (1599), the local clergy was forced to reject the Chaldean Catholic
patriarch of Babylon, who in fact was in full communion with Rome at that time, as a
Nestorian heretic and schismatic. The Portuguese, who controlled the maritime routes to India at that time, continued to block the arrival of eastern bishops. They occupied the diocesan administration of the Saint Thomas Christians and deprived the
archdeacon of his traditional rights. The wait of Syrian Christians for a Syrian bishop to restore their past ecclesiastical dignity and autonomy seemingly came to an end in the arrival of
Ahattalla, a West Syriac bishop. But the Portuguese prevented Ahattalla from entering Malabar, despite the prayers of Archdeacon
Thoma Parambil and the local Christians in 1653. This provoked a strong reaction from the local Christians, led by the archdeacon, in the form of the
Coonan Cross Oath. Although the exact wording of the oath is disputed, its effect was the severing of the relationship between the local Christians and the Portuguese and the proclamation of the archdeacon as their new metropolitan with the title 'Mar Thoma'.
Schism with Pazhayakoottukar In 1656, Pope sent an Italian '
Disclaced' Carmelite priest named
Giuseppe Maria Sebastiani with the aim of bringing back the Saint Thomas Christians who had separated themselves from the jurisdiction of the existing Catholic bishop through the Coonan Cross Oath. In 1659, Sebastiani was appointed as
Apostolic vicar of Malabar with the faculty of appointing a new bishop from the native Christians replacing the Portuguese bishop. He consecrated
Chandy Parambil as the local bishop in 1663, after the
Dutch, having defeated the Portuguese, banned other Europeans from operating in
Malabar. With the presence of another local and validly appointed bishop, Thoma's authority increasingly began to be contested and his many of his followers abandoned him. With this, Thomas wrote letters seeking help from other Eastern churches. In response, a
Syriac Orthodox bishop named
Gregorios Abdal Jalīl arrived in Malabar in 1665 and regularised Thoma's episcopacy. Succeeding Thoma, senior priests in his
Pakalōmaṯṯam dynastic line took over as the leaders of the faction that remained aligned to him. They too maintained strong relations with the Syriac Orthodox Church. Over time, they adopted the West Syriac Rite instead of the old East Syriac Rite. Thus the split in the Saint Thomas Christian community solidified and those who descend from Thoma's faction came to be called ( or 'those of the new allegiance') and those of Chandy came to be called ( or 'those of the old allegiance'). ==Malankara Jacobite Church==