The Diocese of Vellore was started by Salesians in 1952 carving out a portion from the Archdiocese of Madras-Mylapore. Further in 1969, few parishes from the Archdiocese of Pondicherry-Cuddalore were attached to this Diocese. It comprises two civil districts namely Vellore and Tiruvannamalai. There are 84 parishes having Catholic population of 1, 50,000.
The Catholic Mission in North Arcot dates back to 1604. The following chronicles gathered from various sources will give some historical knowledge of this Mission, its foundation and development in the course of over 350 years. The last great prince of the declining Vijayanagar empire (now in Andhra Pradesh), Venkatapathy Deva Rayalu, conquered the kingdom of Vellore in January 1604 and named it Raya Elluru. Elapuri or Elluru in Telugu language would mean city or town. Raya Elluru was meant a town conquered by the king Rayalu and thus the town was named after him – combination of two words Raya and Elapuri.
There were then some Jesuit Fathers at the court of King Rayalu at Chandragiri. He took them also to his new court at Vellore. The word Vellore derives from the Tamil word 'Vel' which means 'spear'; according to another conjecture there were idols of Tamil God 'Murugan' holding 'Vel' in and around Vellore. Vellore was formerly called Velappadi (a place thickly surrounded by a particular tree called 'Velamaram') and for this reason and background the name Vellore came into existence. The Jesuits who had come with their followers here allowed by the King to build again and it is now with the Anglican Church). Ancient Jesuit documents show that among these Jesuits, there was one named Fr. Antonious Rubunus, a preacher and confessor, who was commuting between Chandragiri and Vellore. He was sent to Japan on 12 August 1642. On 22 March 1643 he was martyred at Nagasaki. In 1610, there was a general upheaval against the Jesuits.
The Jesuit residences at Chandragiri and at Vellore were suppressed by a Royal order of the king Philip III of Spain and Portugal in 1611. Formal Christian faith came to the diocese of Vellore towards the last quarter of the 17th century from the Madurai Mission. Fr. Andrew Preyre, S.J. seems to have been the first to evangelise Vellore. St. John de Britto and his disciple Fr. Francis Laynis visited Vellore in 1680 and 1683. Fr. Francis Laynis, (later Bishop of Mylapore), founded in 1683 and 1691 the mission of Koratampet, the first one in the present diocese of Vellore – in the Taluk of Chengam, North Arcot district, some 80 km South-West of Vellore. In 1699 the first French Jesuit Missionaries settled down at Pondicherry, after closing the Mission of Siam. In 1700 a certain Fr. Mandayat began the Jesuit Carnatic Mission at Puliyur, South of Uthiramerur, Chinglepet district like an Indian Sanyasi just as the Fathers of the Madurai Mission did in those days.
Vellore was surrounded by the Mughuls and was taken over by them in the following year. In 1702, Fr. Mandayat founded the mission of Thakkolam (Arakonam Taluk), which was later placed under the care of Fr. Varance Bouchet. In 1703, he was subjected to persecution and was arrested. Later, he was released by the Governor of the Province, Sek Sahib, at the intervention of Fr. Pierre Martin. During the short time he spent at Vellore he decided to erect a chapel and residence under the patronage of Mary. Later, he and his catechist were thrown out of the city after being severely beaten. It was obvious that the Moghuls did not welcome the idea of Christianity getting established at Vellore.