place of worship, albeit secretly. There is evidence of the existence of the tomb (trophoea, i.e., trophies, as signs or memorials of victory) at the beginning of the 3rd century, in the words of the priest Caius refuting the Montanist traditions of a certain Proclus: "But I can show the trophies of the Apostles. For if you will go to the Vatican, or to the Ostian way, you will find the trophies of those who laid the foundations of this church." These tombs were the objects of pilgrimage during the ages of persecution, and it will be found recorded in certain Acts of the Martyrs that they were seized while praying at the tombs of the Apostles. During the reign of the Roman Emperor Valerian, Christian persecution was particularly severe. The remains of the dead, and particularly the Christian dead, had lost their usual protections under Roman law. Some have conjectured that the remains of Peter and Paul may have been removed temporarily from their original tombs in order to preserve them from desecration by the Romans. They may have been removed secretly by night and hidden in the Catacombs of St Sebastian in 258 AD, being returned to their original tombs in 260 when Valerian's reign ended. However, no evidence exists to verify these claims. Constantine's basilica When the Church was once more at peace under Constantine the Great, Christians were able at last to build edifices suitable for the celebration of Mass. The resting places of the relics of the Apostles were naturally among the first to be selected as the sites of great basilicas. The emperor supplied funds for these buildings. Between 320 and 327, Constantine built a five-aisled basilica atop the early Christian necropolis that was purported to be Peter's resting place. Much of the Vatican Hill was leveled to provide a firm foundation for the first St. Peter's Basilica. The altar of the Basilica was planned to be located directly over the tomb. The matter was complicated by the upper chamber or memoria above the vault. This upper chamber had become endeared to the Romans during the ages of persecution, and they were unwilling that it should be destroyed. The memoria was turned into the Chapel of the Confession. Above that was the main floor of the Basilica, with the raised altar directly over the Chapel of the Confession. The Book of Popes details certain