Christianity is believed to have reached India soon after the crucifixion of Jesus. The history of Indian Christianity begins in 52 A.D. when St. Thomas is believed to have arrived in the country. There are historical evidences showing that a group of syro-jewish traders under the leadership of Knai Thomman reached Kodungalloor (Mahodayapuram), in the Kerala coast. The followers of this Thomman in Kerala are known as knanayars. These Christians were known also as Syrian Christians and Nasranis. Even before Christianity became popular and widespread in Europe, this religion has taken strong roots in Kerala and from there to other parts of India. The Roman Catholic sect reached Kerala when Vasco da Gama brought to Kerala coast the first group of European (Portuguese) traders, paving the way for the European colonization of India. It was these Portuguese who spread the message of Roman Catholic sect in Kerala and other parts of India. Several Christian missionaries and other evangelists reached India in unison with the pace of colonization of the country. Being actively involved in educational and social fields in the country, they made vigorous attempts in a systematic manner for the propagation of Christian teachings and in religious conversion.
In the north eastern states of India a very large number of people belonging to the local tribes converted into Christianity. Majority of people in the states of Meghalaya, Nagaland and Mizoram are now Christians. At the same time they retain their tribal beliefs and customs. Christianity has very sound basis in the southern states of Kerala and Tamil Nadu. Though a minority religion, Christianity enjoys in India today the third place in rank, after Hinduism and Islam. In Kerala, as in Tamil Nadu, the Christians play a crucial and decisive role, as the Muslims, in the social, political and educational fields.