Saul was a Jewish Pharisee (a religious conservative) who persecuted the new sect of Christians until he was converted and temporarily blinded by a vision of Christ during a journey to Damascus. He took the name Paul and preached Christianity to the Greek-speaking peoples of Asia Minor and the Mediterranean Basin. He was one of the Apostles, but not among the original twelve.
He was arrested and as a Roman citizen demanded to be tried in Rome, where he was beheaded: hence his attribute, the sword. His life is described in the Acts of the Apostles. His letters to the churches he founded had a profound influence on the development of Christianity: his second symbol is a book.