In the early ages the Christians had no churches—­they met secretly in private houses.  Later, when the cruel pagan emperors began to persecute and put to death the Christians, they made large tunnels under ground and in these places they heard Mass and received the Sacraments.  These underground churches were called the catacombs, and some of them may still be seen at Rome.  In these catacombs, too, the Christians buried their dead, especially the bodies of the holy martyrs.  On their tombs—­generally of stone—­Mass was celebrated.

In every altar the table, or flat part on which the priest celebrates Mass, should be of stone; but if the altar is made of wood, then at least the part just in front of the tabernacle must be of stone and large enough to hold say two chalices—­that is, about ten or twelve inches square.  In this stone are placed some relics of the holy martyrs.  A piece is cut out of the stone and the relic placed in the opening.  Then the bishop puts the little piece of stone back into its place over the relic, seals the opening, blesses the stone, and gives it to the Church.  This is called the altar stone.  You cannot see it because it is covered with the altar cloth; but unless it is in the altar the priest cannot say Mass.  This stone reminds us of the stone tombs of the saints upon which Mass was celebrated.

The Church—­that is, the Christians—­was persecuted for about three hundred years after the death of Our Lord.  These persecutions took place at ten different times and under ten different Roman emperors.  Orders were given to put to death all the Christians wherever they could be found.  Some were cast into prison, some exiled, some taken to the Roman Coliseum—­an immense building constructed for public amusements—­where they were put to death in the most terrible manner in the presence of the emperor and people assembled to witness these fearful scenes.  Some were stripped of their clothing and left standing alone while savage beasts, wild with hunger, were let loose upon them.  Sometimes by a miracle of God the animals would not harm them, and then the Christians were either put to death by the sword, mangled by some terrible machine, or burned.  In these dreadful sufferings the Christians remained faithful and firm, though they could have saved their lives by denying Our Lord or offering sacrifice to idols.  The few who through fear did deny their faith are now forgotten and unknown; while those who remained steadfast are honored as saints in Heaven and upon earth; the Church sings their praises and tells every year of their holy lives and triumph over all their enemies.