Christianity is India's third-largest religion, following Hinduism and Islam. According to tradition, there have been Christians in India almost for as long as the religion has existed, and Christianity underwent major growth following European contact and British colonization, which brought in both Catholic and Protestant missionaries. The 2001 census recorded over 24 million (2.4 crore) Indian Christians, comprising 2.3% of the country's population. There are two main regional concentrations of Christian population, namely in South India and among tribal people in East and Northeast India.
The first Christians in India, were converted by St Thomas the Apostle, who arrived at Kodungallur on the Malabar Coast of India in 52 AD. After evangelizing in Kerala and Tamil Nadu, the Apostle is believed to have been killed in Chennai and buried on the site of San Thome Cathedral. Members of the Syro-Malabar Church, an eastern rite of the Roman Catholic Church, adopted the Syriac liturgy dating from fourth century Antioch. The Christian community founded by St Thomas has since developed into a number of churches, including Syriac-rite churches in communion with the Holy See, Oriental Orthodox churches, and so-called 'Nestorian' churches.
Portuguese missionaries, who reached the Malabar Coast in the late 15th century, made contact with the St Thomas Christians in Kerala, and sought to introduce among them the Latin Rite of the Roman Catholic Church. Throughout this period, foreign missionaries also made many new converts to Christianity. Early Roman Catholic missionaries, particularly the Portuguese, led by the Jesuit St Francis Xavier (1506-52), expanded from their bases on the west coast making many converts. However unlike present missionaries who seek to convert the lower castes and outcastes, Portuguese missionaries sought to convert the entire Hindu population of Goa. St. Francis Xavier, in a 1545 letter to John III of Portugal, requested for an Inquisition to be installed in Goa. However, it was not installed until after eight years of Francis Xavier's death. During the Goa Inquisition under the Portuguese, Hindus were forced to convert and thousands of Hindus in Goa who refused or were suspected of practising heresy were burnt alive in public.Thus present Goa has a huge Roman Catholic population.The undecayed body of Saint Francis Xavier is still on public view in a glass coffin at the Basilica of Bom Jesus in Goa.
Beginning in the eighteenth century, Protestant missionaries began to work throughout India, leading to the growth of Christian communities of many varieties.