Thomas, who was also known as Didymus, was one of the Twelve Apostles of Jesus Christ.  Often remembered for one remark, he was branded “Doubting Thomas.  However, he made what is one of the most explicit statements of faith in the New Testament, “My Lord and my God.”   Those two instances also brought from Jesus a compliment to all later Christians, “Because thou hast seen me, Thomas, thou hast believed; blessed are they that have not seen, and have believed” (John 20:29).

Saint Thomas should also be known for his courage. He expressed a willingness to die for Jesus.  Jesus proposed to go to Bethany to visit Lazarus. Bethany was near Jerusalem, which meant He would be walking into the very midst of his enemies and to an almost certain death. Thomas said to the other apostles, “Let us also go to die with him” (John 11:16b).

Accounts of Thomas’ missionary activities are unreliable, but the most widely accepted account says that he preached in India, although he was reluctant to start the mission. According to the Acta Thomae, the apostles divided up the world for their missionary labors, and India fell to Thomas. However, Thomas claimed that he was not healthy enough and that a Hebrew could not teach Indians; even a vision of Christ could not change his mind. Christ then appeared to a merchant and sold Thomas to him as a slave for his master, a king who ruled over part of India. One story suggests that Thomas offered to build a palace for the Indian king that would last forever. The king gave him money, which Thomas gave to the poor. Asked to show his progress, St. Thomas explained that the palace he was building was in heaven, not on earth. Ultimately, after giving into God’s will, Thomas was freed from slavery. He planted seeds for the new Church, forming many parishes and building many churches along the way.

To this day, Saint Thomas is venerated as the Apostle of India. In fact, there exists a population of Christians along the Malabar Coast, on the western coast of India, who lay claim to conversion by St. Thomas. Their tradition holds that he built seven churches, was martyred during prayer by a spearing on the “Big Hill” near Madras, and was buried in Mylapore, on the east coast of India. Ultimately, St. Thomas’ remains were transported to Ortona, Italy, where they reside today.

Sources:
https://www.newadvent.org/cathen/14658b.htm