Pakalomattom Geevarghese Kathanar, the Archdeacon (Arkkadiyakkon) of the Saint Thomas Christians, died in 1637. Following his death, Thomas, a relative of Geevarghese, was appointed as the next Archdeacon by Archbishop
Stephen Britto. In 1653, Thomas and his followers took the Coonan Cross Oath, declaring that they would no longer obey Archbishop Garcia or any other prelate from the
Society of Jesus, and they vowed to exclude the Jesuits from Malabar and their churches. Of these, three later returned to the
Catholic faction of the St. Thomas Christians. Four months after the Coonan Cross Oath, on 22 May 1653, twelve priests ordained Thomas as the first Bishop of the Malankara See through the act of laying hands on him collectively. However, the Catholic faction disputed the validity of this consecration, arguing that it was irregular. It is claimed that the consecration was regularized by
Gregorios Abdal Jaleel, a delegate of the
Patriarch of Antioch, in 1665, although the exact place and date remain unknown. Thomas adopted the name Mar Thoma, asserting his role as the successor of
St. Thomas the Apostle. This consecration was not accepted by two Southist churches, one at
Kaduthuruthy and another at
Udayamperoor. Later, Bishop Sebastiani, who was ordained on 15 December 1659, convinced many priests and laypeople, including the three advisors who had initially supported Mar Thoma, that the consecration was irregular. Due to political and financial pressures exerted by the
Carmelite fathers through the
Portuguese and native kings, many churches and laypeople withdrew their allegiance to Mar Thoma. They requested that he relinquish his episcopal dignity, but Mar Thoma continued to perform episcopal functions. As a result, the Malankara Church split into two factions: one led by Mar Thoma I and the other by Bishop
Palliveettil Mar Chandy, also known as Alexander de Campo. Both claimed to have Apostolic briefs of appointment as Bishop. To resolve the dispute, the case was referred to the King of Cochin. On 20 September 1661, the King requested that both parties present their Apostolic briefs in his court.
The Apostolic Commissary was able to produce briefs from the
Pope of Rome, while the Archdeacon's party failed to present any. On 9 October 1661 Bishop Sebastiani attempted to capture Mar Thoma with the assistance of Portuguese forces and local allies, but Mar Thoma and his followers managed to escape the night before, disguising themselves as soldiers to avoid recognition. ==Rise of Dutch power==