The Apostolic Church of St. Thomas Christians has its origin from St. Thomas, the Apostle who arrived on the Kerala coast in A.D. 52. The Metropolitan of "The See of St. Thomas" was "Metropolitan and Gate of all India". In the course of history this Church entered into hierarchical relationship with the East Syrian Church and became an autonomous Metropolitan See under the East Syrian Patriarch in communion with the Apostolic See of Rome. The " Archdeacon of all India" did the administration.

The Portuguese Fathers who arrived in the 15th century could not tolerate the liturgical traditions and the mode of governance of this church. They latinized the ancient liturgical texts. A section of the community broke away from the Western supremacy in 1653. They constitute the present Malankara Orthodox Churches. We are the descendants of those who stayed back, maintaining loyalty to the Apostolic See of Rome.

The Archdiocese of Changanacherry is one of the first two Vicariates and the second Metropolitan Archdiocese of the Syro - Malabar Church, after the establishment of the Syro - Malabar hierarchy, which was the prelude to the restoration of the identity of our Church in 1992 as Sui Juris Church, thanks to the untiring efforts of our forefathers.

Pope Leo XIII of happy memory by his Bull "Quod Jam Pridem" dated May 20, 1887 established two Vicariates Apostolic, viz, Kottayam and Thrissur exclusively for the Syro - Malabarians and Dr Charles Lavigne and Dr Adolph Medlycott respectively were appointed Vicars Apostolic.

The same Pope reorganized the existing Vicariates by the Bull "Quae Rei Sacrae" dated July 28, 1896 establishing a new vicariate, Ernakulam, with territories carved out from the two existing Vicariates (Pallippuram, Edappaly and Arakuzha divisions from Kottayam Vicariate).

The Vicariate of Kottayam was renamed Changanacherry, since this town had been the centre of Catholic activity, for e.g. the convocation of the Changanacherry Synod in 1888 and hence its headquarters had been shifted to Changanacherry.

Indigenous bishops were appointed Vicars Apostolic to the new Sees. They were Mar Mathew Makil for Changanacherry, Mar Louis Pazheparambil (from Changanacherry Vicariate) for Ernakulam and Mar John Menacherry for Thrissur.

A new Vicariate of Kottayam was constituted in 1911 exclusively for the Suddists and Mar Mathew Makil was tansferred to Kottayam as the Vicar. Apostolic of Suddists and Mar Thomas Kurialacherry was appointed the Vicar Apostolic of Changanacherry.

With the establishment of the Syro - Malabar Hierarchy on December 21, 1923 by the Bull "Romani Pontifices" of Pope Pius XI, the Diocese of Thrissur, Changanacherry and kottayam became Suffragans of the Archdiocese of Ernakulam thereby constituting the first Syro - Malabar Province.

On July 25, 1950 the Diocese of Changanacherry was bifurcated by the Bull "Quo Ecclesiarum" of Pope Pius XII and the new Diocese of Palai was created.

The Holy See being very much pleased with the wonderful progress achieved by the Syro - Malabarians, extended the hitherto held boundaries of Changanacherry to the areas south of river Pumba, upto (including) Kanyakumari, by the Bull "Multorum Fidelium" of Pope Pius XII, dated April 29,1955.

Changanacherry was raised to the status of an Archdiocese on July 26, 1956 by Pope Pius XII constituting the second province in the Syro - Malabar Church and Kottayam and Pala became its suffragans. The Apostolic Constitution 'Regnum Coelorum' of November 26, 1959 of Pope John XXIII gave effect to this decision.

The Archdiocese was again divided on February 26, 1977 by the Bull "Nos Beati Petri" of Pope Paul VI and the new Diocese of Kanjirapally was set up comprising parts of the civil districts of Kottayam, Idukki and Kollam.

The Archdiocese was divided a fifth 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 December 18, 1996. The formal inauguration of the new diocese of Thuckalay and the Episcopal Ordination of Mar George Alenchery as its first Bishop took place on February 2, 1997.

In 1975 the Church work of five civil districts of the Archdiocese of Agra in the State of Uttar Pradesh was taken up completely by the Archdiocese of Changanacherry.

Name	Designation	Period
Most Rev. Mar Joseph Perumthottam	Auxiliary Bishop	2002-2007
His Eminence Antony Padiyara	Archbishop	1970-1985
Most Rev. Mathew Kavukattu	Archbishop	1950-1969
Most Rev. James Kalassery	Bishop	1927-1949
Most Rev. Thomas Kurialachery	Bishop	1911-1925
Most Rev. Mathew Makil	Bishop	1896-1911
Most Rev. Charles Lavigne	Bishop	1887-1896