The Papal Basilica of Saint Paul Outside the Walls (Italian: Basilica Papale di San Paolo fuori le Mura), commonly known as Saint Paul's Outside the Walls, is one of Rome's four major papal basilicas, along with the basilicas of Saint John in the Lateran, Saint Peter's, and Saint Mary Major, as well as one of the Seven Pilgrim Churches of Rome.
The basilica was founded by the Roman Emperor Constantine I over the burial place of Saint Paul, where it was said that, after the Apostle's execution, his followers erected a memorial, called a cella memoriae. This first basilica was consecrated by Pope Sylvester in 324.