Below the Papal altar, protected by an enormous wrought iron cage, lie two bronze doors, covered with reliefs and inscriptions dating from the 13th century. These decorations cover the cypress wood ark, specifically made by Leo III to contain the illustrious treasures and relics of the Sancta Sanctorum. In 1902, the grate was opened for the first time since 1521, after Father F. Jubaru S.J. got the permission to examine the head of Saint Agnes which was kept within. In 1905, F. H.Grisar, was allowed to open it once again to study the magnificent collection of sacred objects made of gold, silver, ivory, and precious woods, together with numerous relic holders, crosses, fabrics, brocades, parchments, miniatures and enamels, all of incalculable value – a veritable treasure chest. The reliquaries were transferred to the Sacred Christian Museum in the Vatican library. Among the relics kept at this site were the heads of the apostles Peter and Paul, which are now venerated in the Basilica of Saint John Lateran.