The present structure dates probably from the time of Liberius, in the middle of the fourth century. The indefatigable Damasus made a marble pavement--_fecit platoniam_--and seems to refer to the legend in the following rather unclassical metrical inscription: HIC HABITASSE PRIVS SANCTOS COGNOSCERE DEBES NOMINA QVISQVE PETRI PARITER PAVLIQVE REQVIRIS DISCIPVLOS ORIENS MISIT QVOD SPONTE FATEMVR SANGVINIS OB MERITVM CHRISTVMQVE PER ASTRA SEQVVTI AETHERIOS PETIERE SINVS ET REGNA PIORVM ROMA SVOS POTIVS MERVIT DEFENDERE CIVES HAEC DAMASVS VESTRAS REFERAT NOVA SIDERA LAVDES. “Here, you must know, that saints once dwelt. If you ask their names, they were Peter and Paul. The East sent disciples, as we 187 willingly acknowledge. The saints themselves had, by the merit of their bloodshedding, followed Christ to the stars, and sought the home of heaven and the kingdoms of the blest. Rome, however, obtained to defend her own citizens. These things may Damasus be allowed to record for your praise, O new stars of the heavenly host.” [Illustration: Fig. 27.--Plan of Crypt of Saint Peter and Saint Paul.] Figs. 27 and 28 show the plan and perspective of the crypt. D is the chamber and E the subterranean vault. Around the wall are twelve _arcosolia_, in front of which runs a low stone seat. In the centre is an opening in the floor widening into a vaulted and frescoed marble tomb about six feet square and as many deep. Here, according to tradition, the two great apostles lay side by side in death; and to this spot was especially given for many centuries the name _Catacumbæ_. A door out of the left aisle of the church leads to the Catacomb proper. This, having been so long open, has been despoiled of every object of interest, and nearly all the monuments and inscriptions have been removed to the museums of the city. Though of considerable 188 extent, it is not nearly as large as some others. Previous to De Rossi’s exploration of the Catacomb of Callixtus in 1854 it was confounded with that cemetery, but he has shown that opinion to be erroneous. [Illustration: Fig. 28.--Crypt of Saint Peter and Saint Paul.]