ROME — The first-ever scientific test on what are believed to be the remains of the Apostle Paul "seems to confirm" that they do indeed belong to the Roman Catholic saint, Pope Benedict XVI said Sunday.

On Saturday, the Vatican newspaper L'Osservatore Romano announced the June 19 discovery of a fresco inside another tomb depicting St. Paul, which Vatican officials said represented the oldest known icon of the apostle. Link

Paul and Peter are the two main figures known for spreading the Christian faith after the death of Christ.
According to tradition, St. Paul, also known as the apostle of the Gentiles, was beheaded in Rome in the 1st century during the persecution of early Christians by Roman emperors. Popular belief holds that bone fragments from his head are in another Rome basilica, St. John Lateran, with his other remains inside the sarcophagus.

Very interesting read