Thomas the Apostle was one of the twelve disciples of Jesus Christ. He is often referred to as "Doubting Thomas" because he initially doubted the resurrection of Jesus until he saw the wounds from the crucifixion. His story is primarily found in the New Testament, particularly in the Gospel of John. After the resurrection, Thomas declared his faith upon seeing Jesus, saying, "My Lord and my God." He is believed to have traveled to spread the teachings of Jesus, with traditions suggesting he preached in places like India. Thomas is also recognized as a martyr for his faith.