The Saint Thomas Christians are an ancient body of Christians from Kerala, India, who trace their origins to the evangelistic activity of Thomas the Apostle in the 1st century. They are also known as "Nasranis" as well. The Syriac term "Nasrani" is still used by St. Thomas Christians in Kerala.
They are also called Syrian Christians because of their use of Syriac, which is a dialect of Aramaic, in liturgy. (See also Aramaic of Jesus.) They are also known as Malabar / Malankara Mar Thoma Nasranis, because these Christians are from Kerala that was also known as Malabar or Malankara. Their language is Malayalam, the language of Kerala.
For the first 15 centuries, they had their own leaders to whom they were obedient and who were well respected by both the people and the rulers of the country. In AD 190, Pantaenus from Alexandria visited these Christians. He found that they were using the Gospel of Matthew in the Hebrew language. Around AD 522, an Egyptian monk, Cosmas Indicopleustes, visited the Malabar Coast. He mentions Christians in Malabar (Kerala), in his book Christian Topography. This shows that until the 6th century these Christians had been in close contact with Alexandria.
In AD 883, Alfred the Great (849–899), King of Wessex, England reportedly sent gifts to Mar Thoma Christians of India through Sighelm, bishop of Sherborne. Around AD 1292, Marco Polo (1254–1324) on his return journey from China visited Kerala, mentions that, "The people are idolaters, though there are some Christians and Jews among them".