St. Paul the Apostle was an early Christian missionary and theologian, known for spreading the teachings of Jesus Christ throughout the Roman Empire. Originally named Saul of Tarsus, he was a Pharisee who initially persecuted Christians before experiencing a profound conversion on the road to Damascus. After his conversion, Paul became a key figure in the early church, establishing several Christian communities and writing many letters, known as Epistles, that form a significant part of the New Testament. His teachings emphasized faith, grace, and the importance of spreading the Gospel message.