 They may have been removed secretly by night and hidden in the Catacombs of S. Sebastiano in 258 AD, being returned to their original tombs in 260 when Valerian's reign ended.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.