Question:
Answer:
The only things we know for sure about St. Thomas are found in the Gospel of John. Unfortunately, it does not tell us where St. Thomas went to preach after Pentecost.
The apocryphal work Acts of Thomas describes him ending up in India through a miraculous set of occurrences and then experiencing many miraculous events. Many early Christian writers repeated the tradition that St. Thomas preached in India. In the sixth century there were Christians present in India who used a Syriac-based liturgy.
However, we know that by the fourth century the claimed relics of St. Thomas were in Edessa, which was to the northeast of Israel.
It is certainly possible that St. Thomas went to India as part of his ministry, and there is no other tradition that contradicts a potential mission to India. Part of Southwest India was also under the jurisdiction of Edessa, which could explain why his remains were moved there if he died in India. But no unified tradition exists as to where his ministry was, and this lends some doubt to the veracity of some of the accounts.