"These vast excavations once formed the ancient Christian cemeteries of Rome; they were begun in apostolic times, and continued to be used as burial-places of the faithful till the capture of the city by Alaric in the year 410. In the third century, the Roman Church numbered twenty-five or twenty-six of them, corresponding to the number of her titles, or parishes, within the city; and besides these, there are about twenty others, of smaller dimensions, isolated monuments of special martyrs, or belonging to this or that private family. Originally they all belonged to private families or individuals, the villas or gardens in which they were dug being the property of wealthy citizens who had embraced the faith of Christ, and devoted of their substance to His service. Hence their most ancient titles were taken merely from the names of their lawful owners, many of which still survive. Lucina, for example, who lived in the days of the Apostles, and others of the same family, or at least of the same name, who lived at various periods in the next two centuries; Priscilla, also a contemporary of the Apostles; Flavia Domitilla, niece of Vespasian; Commodilla, whose property lay on the Via Ostiensis; Cyriaca, on the Via Tiburtina; Pretextatus, on the Via Appia; Pontiano, on the Via Portuensis; and the Jordani, Maximus and Thraso, all on the Via Salaria Nova. These names are still attached to the various catacombs, because they were originally begun upon the land of those who bore them. Other catacombs are known by the names of those who presided over their formation, as that of St. Calixtus, on the Via Appia; or St. Mark, on the Via Ardeatina; or of the principal martyrs who were buried in them, as SS. Hermes, Basilla, Protus, and Hyacinthus, on the Via Salaria Vetus; or, lastly, by some peculiarity of their position, as _ad Catacumbas_ on the Via Appia, and _ad duas Lauros_ on the Via Labicana. "It has always been agreed among men of learning who have had an opportunity of examining these excavations, that they were used exclusively by the Christians as places of burial and of holding religious assemblies. Modern research has now placed it beyond a doubt, that they were also originally designed for this purpose and for no other: that they were not deserted sand-pits (_arenariæ_) or quarries, adapted to Christian uses, but a development, with important modifications, of a form of sepulchre not altogether unknown even among the heathen families of Rome, and in common use among the Jews both in Rome and elsewhere.