of Callistus on the Appian Way. There it rested, according to the most recent investigations, until the persecution and confiscation of the cemeteries in A.D. 258, when for security's sake it was secretly removed at the same time as the body of S. Peter was brought from the grave on the Vatican Hill. The sacred remains of the two apostles were laid in the "Platonia" Crypt, in what was subsequently known as the Catacomb of S. Sebastian, on the Via Appia; and probably after an interval of some two years, when the cemeteries were restored to the Christian congregations by the Emperor Gallerius, the bodies of the two apostles were brought back again to their original resting-places.
Anacletus, the third in succession of the Roman bishops, erected in the first century a small "Memoria" or chapel over the tomb of S. Paul, like the one he built over the tomb of S. Peter on the Vatican Hill.
In the year 324-5 the first Christian Emperor, Constantine, over the apostle's tomb and little "Memoria," caused the first important basilica, known as S. Paul's, to be erected; the Emperor treated the loculus or sarcophagus of S. Paul in the same manner as he had treated the sarcophagus of S. Peter, enclosing it in a solid bronze coffin, on which he laid a cross of gold. When the basilica was rebuilt, after the fire of A.D. 1813, a marble slab, which apparently was a part of the vaulted roof of the original sepulchral chamber of the apostle, came to light. On this slab, or rather slabs of marble, which now lie directly under the altar, are engraved the simple words Pavlo Apostolo Mart: the inscription evidently dating from the days of Constantine (A.D. 324-5). No further investigation of the tomb was permitted. It is believed that the bronze sarcophagus with its sacred contents, with the golden cross, lie immediately under the solid masonry upon which the slab of marble we have been speaking of rests.
On the slab of marble in question, besides the simple inscription above quoted, are three apertures: the most important of these is circular; it is, in fact, a little well, and is 23-1/2 inches in depth, and was no doubt originally what is termed the "billicum confessionis," through which handkerchiefs and other objects were lowered, so as to be hallowed
