Among the various historical evidences of primitive Christianity, none seem more authentic or possess a deeper interest than those connected with the catacombs of ancient Rome. These were subterraneous chambers or excavations which were made in the soft, sandy rock which underlies the hills on which stood ancient Rome. To these dreary vaults the early saints were in the habit of retiring, in order to celebrate their worship in times of persecution, and in them were buried many of the saints and martyrs of the primitive church. They consist of long, narrow galleries, {128} usually about eight feet high and five feet wide, which twist and turn in all directions, very much resembling mines. The graves were constructed by hollowing out a portion of the rock at the side of the gallery, large enough to contain the body. The entrance was then built up, and generally an inscription was placed upon it. {127} [ILLUSTRATION: SECTION OF THE CATACOMB OF CALIXTUS.] {128} These excavations were first formed by quarrying the volcanic, sandy rock, in order to supply the materials necessary for the building of ancient Rome. They were afterwards increased in order to procure the sand used for cement, until, at length, they formed an area of very extensive dimensions. They are mentioned by the Roman writers, Horace and Varro, by Cicero and Seutonius. Jerome, writing about the middle of the fourth century, describes them as they existed in his day, declaring that he "was accustomed, as a youth, when studying in Rome, to visit these dark and dreary spots on Sundays, in order to see the tombs of apostles and martyrs." [ILLUSTRATION: BURIAL PLACE IN THE CATACOMBS.] Among the many inscriptions which the museum of the Vatican has derived from the catacombs is {129} the following. It relates to the reign of Marcus Aurelius, or Antoninus, as he is sometimes called, about A. D. 150: ALEXANDER MORTUUS NON EST SED VIVIT SUPER ASTRA ET CORPUS IN HOC TUMULO QUIESCIT. VITAM EXPLEVIT SUB ANTONINO IMPO, QUI UBI MULTUM BENEFITII ANTEVENIRE PRAEVIDERET PRO GRATIA ODIUM REDDIDIT GENUA ENIM FLECTENS VERO DEO SACRIFICATURUS AD SUPPLICIA DUCITUR. TEMPORA INFAUSTA! QUIBUS INTER SACRA ET VOTA NE IN CAVERNIS QUIDEM SALVARI POSSIMUS. QUID MISERIUS VITA SED QUID MISERIUS IN MORTE CUM AB AMICIS ET PARENTIBUS SEPELIRI NEQUEANT TANDEM IN COELO CORUSCANT PARUM VIXIT QUI VIXIT IN X. TEM. TRANSLATION: