St. Paul's body was taken by the faithful to a nearby tomb owned by Matrona Lucilla, a Roman noblewoman who was an early convert to the Faith through the preaching of Peter and Paul. St. Paul, much like the Lord Jesus whom Paul served, was placed in a tomb much like Jesus was.
Over the site, Constantine build a large basilica much like he did over that place St. Peter died.
Giorgio Filippi, the archaeologist of the Vatican Museum, supervised and directed an effort after the report of Matrona Lucilla's tomb was rediscovered beneath Romes second largest basilica. There lies in a stone carved coffin what is believed to be the remains of St. Paul. Mr Filippi would continue, "For now we didn't open the sarcophagus to study the contents. Our aim was to unearth the coffin venerated as St. Paul's tomb, not to authenticate the remains..."