A title applied in a wider sense to all the Christian communities of the Syrian rite living in Kerala in SW India (also known as ‘Thomas Christians’), and in a narrower sense to the community in communion with Rome (the ‘Syro-Malabar Church’). All claim that their Church was founded by St Thomas the Apostle, but there is no certain evidence that there were Christians in India earlier than the 6th cent. They probably came originally from E. Syria. At the Synod of Diamper in 1599 they renounced Nestorius and allied themselves with the RC Church. Though there was a breach with the W. in 1653, about two-thirds of them returned to communion with Rome in 1662. The rest joined the Syrian Orthodox. At the end of the 19th cent. a reforming group of the Syrian Orthodox constituted themselves the ‘Mar Thoma’ Church; this has links with the Church of South India. Another section sought union with Rome and in 1930 the Malankarese Church came into being. Within the Syrian Orthodox Church in India there are two Catholicoi, one recognizing the Patriarch in Damascus, the other independent. Since 1907 there has also been a small community again subject to the Patriarch of the Church of the East.