Saul, who became Paul after his conversion, became the apostle to the Gentiles. The New Testament is filled with testimonies, letters, and instructions to the different churches that were established by Saint Paul. The Gospel was spread through waves by Paul as he preached throughout Europe. Communities came into being at Philippi, Thessalonica, and Corinth. Paul even went to Athens, which was known as the cultural center in ancient times. Here, he debated the Gospel with the Greeks at their own philosophical level.
He traveled to Asia as well as to Europe and encountered many difficulties. The Jews were hostile to him and would not listen to his message of Jesus, the Messiah. Yet he also achieved great strides in transmitting the faith, especially in Corinth. In all, he embarked on four journeys. The last journey took him to Rome, where he was taken prisoner. On his way to Jerusalem, he became involved in a political riot, was arrested, and was sent to a prison in Caesarea. There he claimed his rights as a Roman citizen, appealed to the emperor, and was transferred to Rome. He reached the city two years after his arrest, all the while preaching the Gospel.
It is believed that he was eventually freed, traveled to Spain, and later returned to Asia Minor and Greece. The New Testament Letters to Timothy and Titus confirm this time period. Once again, Paul was taken as prisoner to Rome. He was executed in 67 AD. In his letter (95 AD) to the Church of Corinth, Pope Clement alludes to the fact that both Peter and Paul were executed in Rome. Peter, since he was not a Roman citizen, was crucified; Paul, a Roman citizen, was beheaded. Beheading was a quicker form of death and therefore considered more humane.
Paul is considered one of the pillars of the Roman Catholic Church because of his missionary activity in Rome and his eventual martyrdom.
In his letter to the Corinthians, Pope Clement gives testimony to the legacy of Paul. He said that Paul showed great endurance all through his imprisonments, exiles, and attempted stoning, and should be considered a man of noble faith. He gave his testimony before rulers, philosophers, and ordinary people. Paul was one of the greatest men who witnessed to Jesus Christ and expanded Christianity by his testimony.