The apostle Thomas was also known as Didymas (the twin.) As to who his twin was, it's not known. By trade, he was a fisherman and a native of Galilee in Israel.
After the resurrection of the Lord Christ Jesus, Thomas went to Babylon; it is believed that he established the first Christian church there.
Thomas is also known to have gone to Persia and from there he went to India and preached the Gospel making many converts. It is believed that Thomas arrived in India no later than 49 AD.
It is also believed that the apostle Thomas evangelized as far as China, and while in India, he suffered martyrdom (he was killed with a lance and buried in Mylapore, India, which is now a suburb of Madras.) It is believed that he died on the 21st of December.
The apostle Thomas is said to have been a fearless evangelist and a great builder of churches.
The information above is compiled from the book "The Search for the Twelve Apostles" by William Steuart McBirnie Ph.D, Copyright 1973