South India is the cradle of Dravidian languages, cultures and religions. These are distinct from Sanskrit and can stand without it. South India is also the birthplace of the St Thomas Christians, who trace their history to the ministry of the Apostle Thomas (52–72 ce) in modern-day Kerala and in Mylapore, near Chennai in Tamil Nadu. As time passed, they interacted with the leaders of the Orthodox Churches in Syria and Persia; the Catholic Christians and missionaries from Portugal, Italy and Spain; the Protestant colonial administrators, traders and missionaries from Europe and North America; and the Pentecostal and Charismatic Christians from both within and outside India. Some South Indian Christians had no contact with any non-Indian Christians and learned to perceive and interpret the received texts of the Bible in their own way. Thus, contemporary Christianity in South India remains active, kaleidoscopic, complex and intricate.

Orthodox Christianity in South India has the longest and most complex history. Their members are native to Kerala; yet most of them faithfully carry on the legacies of their ancestors, who were loyal to either the Patriarchs in Persia and Constantinople or the Popes in Rome. These legacies include their hierarchy, liturgies, theologies, vestments, governance, and marriage and funeral customs. Some of them are proud of their church leaders, who associated themselves either with the Portuguese Catholic Christians or the English Anglicans. Under these external ties and Christian manifestations lie the forces of caste identity, rivalries among influential families, desire to control immovable properties and access to international ecumenical bodies. Nowadays, the Syro-Malabar Church remains Catholic. The Chaldean Syrian Church relates itself to the Assyrian Church of the East. The Malankara Syriac Orthodox Church has branched into four distinct bodies, namely the Jacobites, the Syrian Orthodox, the Syro-Malankara and the Mar Thoma. The leaders of the Mar Thoma Christians (e.g. M. M. Thomas) are influential and vocal in missionary and ecumenical movements both inside and outside India. They occupy key positions in theological, medical, educational and ecumenical institutions. Their representatives live in nearly every major town and city in the world, regularly meeting for worship services and cultural events. They practise endogamy and consciously maintain fellowship with each other even in diaspora contexts.