The great ancestor of our Archdiocese is the Carnatic Church work, which was started around the year 1700. This Carnatic Church work was known as Church work of the Coromandel Coast and also as the Malabar Church work.
 
Before the establishment of the Carnatic Church work in 1700, the Jesuit Fathers of the Madurai Church work, especially , St. John de Britto came into the Gingee Kingdom after 1660 and preached the Gospel up to the Palar river, South of Madras. Also, some religious belonging to various orders, looked after the spiritual needs of the European communities to a certain extent in their trading centres along the coastal area like Cuddalore, Porto Novo etc., The French Capuchins first settled in Pondicherry in 1674 and the French Jesuits, expelled from Siam (Thailand) also took refuge in Pondicherry in 1693. But, in 1693, the Dutch chased away all the religious from Pondicherry and they could come back only in 1699. While the Capuchins were looking after the Europeans in Pondicherry, the French Jesuits organized the Carnatic Church work for the Indian people.

Boundaries of Carnatic Church work
The boundaries of the Carnatic Church work were as follows: on the south and west, the Pennaiyar River, beyond which were the Madurai Church work and the Mysore Church work - on the east, the Bay of Bengal, and on the north, Kurnool including the Krishna and Godavari areas near the sea shore.
 
The Church work affected badly
The continual wars in the 18th century, the ruin of Pondicherry town in 1761 and the suppression of the Society of Jesus in 1773, hit badly this vast Carnatic Church work.  
 
Jesuits replaced by Foreign Church work Fathers
In 1776, the French Jesuit fathers were replaced at the order of Rome by the Foreign Church work French Fathers. Although the bishop of these new Fathers had all the power of jurisdiction, he was not titled “Vicar Apostolic”, but only “Superior of the Church work of the Coromandel Coast” .Rome successively gave him jurisdiction over the other Church work, in the Madurai, Coimbatore and Mysore areas, affected by the suppression of the Society of Jesus.  So, around 1800, the extent of the Carnatic Church work was immense, although the workers were very few.
 
Reorganization
The Carnatic Church work was reorganized when new Vicariates Apostolic were created: Vicariate Apostolic of Madras in 1832, of Madurai in 1836 - 46 and the Vicariates of Visakapattnam, Mysore and Coimbatore in1845 - 50.  
 
The First Vicar Apostolic and First Archbishop 
Pondicherry became a Vicariate Apostolic of the Coromandel Church work on September 1, 1836, with Msgr. Bonnand as the first Vicar Apostolic. This Vicariate Apostolic was raised to an Archbishopric on June 17, 1887, with Msgr. Laouenan as the first Archbishop.
 
Subdivisions of the Archdiocese  
Subsequently, subdivisions of the Archdiocese took place, erecting the new Dioceses of Kumbakonam in1899, of Vellore in 1928 and Salem in 1930 . On a reorganization of the diocese by Rome in1969, Kanjeevaram and Madurantagam taluks of Chinglepet district were transferred to the Archdiocese of Madras and the Tiruvannamalai Taluk to Vellore .
 
The New Name
As the Archdiocese of Pondicherry extended over the Pondicherry Union territory and the South Arcot district of Madras state, it was given a new title by Rome: ”Archdiocese of Pondicherry and Cuddalore” on August 7, 1953.
 
The extent of the present Archdiocese
Originally, this Archdiocese was looking after the ex -French settlements of the Pondicherry Union territory namely Karaikal, Chandranagore, Mahe. Yanam another ex-French settlement which was always looked after by the MSFS Fathers of Vizagapattinam.  Chandranagore was re-allocated to the Archdiocese of Calcutta and Mahe to the Diocese of Calicut in Kerala in 1949. The present Archdiocese of Pondicherry and Cuddalore extends over the Pondicherry and Karaikal districts of the Pondicherry union territory, and the taluks of Cuddalore, Panruti, Vridhachalam, Tittagudi and Chidambaram (exclusive of area south of the river Vellar) of the south Arcot district, and the Villupuram, Gingee, Tindivanam, Vanur, Tirukovilur, Ulundurpet, Kallakurichi and Sankarpuram taluks of Villupuram district in Tamil Nadu.