They Latinized the ancient liturgical texts and forced existing East Syriac Christians or Nasranis to convert to the Roman Catholic Church under the Padroado Archbishop of Goa.

When the domination of the Portuguese missionaries became unbearable, a section of this community broke away from western supremacy in 1653 and accepted allegiance to Antiochian West Syriac Rite and Miaphysite belief.

This relationship started only in 1553 as a half Catholic-half Nestorian position due to a split in the Babylonian Church of the East and strengthened in 1599 through the Udayamperur sunnahadose (Synod of Diamper).

Pope Leo XIII of happy memory by his Bull ‘Quod Iam Pridem’ dated 20 May 1887 established two Vicariates Apostolic - Kottayam and Thrissur; exclusively for the Syro-Malabarians.

The Holy See being impressed by the wonderful progress achieved by the Syro-Malabarians, extended the hitherto held boundaries of Changanacherry to the areas south of river Pamba, up to (including) Kanyakumari, by the Bull ‘Multorum Fidelium’ of Pope Pius XII, dated 29 April 1955.

The Archdiocese was again divided on 26 February 1977 by the Bull ‘Nos Beati Petri’ of Pope Paul VI and the new Eparchy of Kanjirappilly was set up comprising parts of the Civil districts of Kottayam and Idukki.

The Archeparchy was divided a fourth time when its Kanyakumari Mission was elevated to the status of a new diocese by the Bull Apud Indorum Gentes of John Paul II, dated 18 December 1996.