The Porta Santa (Holy Door), the work of the Sienese sculptor Vico Consorti (1902-97), was installed in 1949.
The Porta Santais only open during a Jubilee, or Holy Year, which normally takes place every twenty-five years. For the rest of the time the door remains closed and walled up on the inside. The Holy Door represents Jesus, the Good Shepherd and the sheep pen: "I am the door: by me if any man enter in, he shall be saved, and shall go in and out, and find pasture." (John 10:9, KJV).
The sixteen bronze panels are divided into groups of four by the coats of arms of popes who have celebrated Jubilee years. The panels depict scenes from the bible, apart from the bottom-right panel, which depicts Pope Pius XII (r. 1939-58) opening the Holy Door to mark the start of the 1950 Jubilee.