When 16th century European priests arrived in southern India to introduce Christianity, they were told that a more famed Christian missionary had been there first. In the districts of Travancore and Cochin, there was already a community of Indian Christians with a tradition of loose communion with the Roman Catholic Church. The man who first converted them, the Indians said, was none other than St. Thomas the Apostle (the "Doubting Thomas"), who reputedly arrived in India aboard a Roman trading vessel in 52 A.D.
Whether St. Thomas actually preached under the palm trees of Travancore and Cochin is a point that historians...