The “Via Appia” led from the ancient Porta Capena through Albano, Aricia, etc., on to Capua, and later it was continued to Brindisi. Three of the four groups of cemeteries or catacombs coming from Rome are on the right of the way: the cemetery of S. Callistus, of S. Sebastian (“ad Catacombas”), of S. Soteris; and on the left that of Prætextatus.

We have alluded above to the ancient Pilgrim Itineraries as giving a sure index to De Rossi in his investigation and exploration work. As an example we append a short extract from the older of the two Pilgrim Guides known as the Salzburg Itinerary, which dates from about the year of grace 625: “You come by the Appian Way to S. Sebastian Martyr, whose body lies deep down; there too are the sepulchres of the Apostles Peter and Paul, in which they rested for 40 years.... North on the same Appian Way you come to the Martyrs Tiburtius, Valerianus, and Maximus. When there you pass into a large crypt and you find S. Urban, Martyr and Confessor; in another spot Felicissimus and Agapitus, Martyrs; in a third place, Cyrinus Martyr; in a fourth, Januarius Martyr. On the same way you find S. Cecilia and a countless multitude of martyrs (‘ibi innumerabilis multitudo Martyrum’), Sixtus Pope and Martyr, Dionysius Pope and Martyr, Julianus Pope and Martyr, Flavianus Pope and Martyr. There are 80 martyrs resting there. Zephyrinus Pope and Martyr rests above Eusebius; and Cornelius Pope and Martyr rests in a crypt a little further off; and then you come to the holy Virgin and Martyr Soteris.”

Comparing the various Pilgrim Guides together, De Rossi found that, with very minor differences in the details, they agreed wonderfully; and in the main, although composed a thousand to thirteen hundred years ago, he was able with their help to identify the principal shrines visited by the pilgrim crowds of the sixth and two following centuries.

(1) The Cemetery of S. Sebastian (“ad Catacombas”) is situated on the Via Appia, right-hand side; about one and a half miles from the Porta S. Sebastiana (the ancient Porta Appia). The principal “memory” belonging to this catacomb is the Platonia chamber—so called from its having been lined with marble—in which for a brief season were deposited the bodies of the two Apostles SS. Peter and Paul. The fact of this chamber having been the temporary home of the sacred bodies is undisputed; the exact date of their having been placed there, and the length of the period during which they were left in the Platonia chamber in question, have been the subject of much controversy. The period of forty years mentioned in the above-quoted Pilgrim Itinerary is now reduced by the most dependable of modern scholars to two years, and the date of the placing of the bodies in this spot is now generally assumed to have been A.D. 258, in the days of the short but bitter persecution of Valerian, when the tombs on the Vatican Hill and on the Via Ostiensis were not considered safe from outrage. When the active persecution ceased, the remains of the two apostles were restored to their original resting-places; the spot, however, where the sacred bodies had rested for a brief season assumed in the eyes of the faithful a singular sanctity, and very many desired to be laid in the immediate neighbourhood of the hallowed place. This was no doubt the original reason for the formation of the Cemetery “ad Catacombas,” the name of the little district in which the temporary tomb of the two apostles was situated.

The catacomb in question was eventually named after Sebastian, a brave confessor in the persecution of Diocletian, circa A.D. 289–303. This Sebastian was tribune in the first cohort and commanded a company of the Prætorians, which was stationed on guard on the Palatine. He died for his faith under circumstances of a peculiar dramatic interest, being pierced with arrows and cruelly scourged. His body, so runs the probably true story, was taken out of the common sewer, into which it was ignominiously thrown, by a Christian matron named Lucina, who reverently interred it in the Cemetery “ad Catacombas” in the neighbourhood of the sacred Platonia chamber.

The remains of S. Sebastian were removed in the seventeenth century by Cardinal Borghesi from the crypt in which they were originally deposited and re-interred in the modern chapel which was erected over the ancient sanctuary. During the Middle Ages, when owing to the raids of the barbarians and consequent translation of the more celebrated martyrs to churches within the city, the eventful story of the catacombs was forgotten, this cemetery, owing to its connection with the two great apostles, was ever a hallowed sanctuary, and was visited by an unbroken stream of pilgrim visitors, and after the rediscovery of the City of the Dead in the sixteenth and seventeenth centuries, gave the name of its now famous district “ad Catacombas” to the various subterranean cemeteries which from time to time since then have been discovered.

The corridors with their graves in this famous cemetery have not yet been fully excavated.

The Cemetery of S. Callistus.—The great group of catacombs generally known under the title “S. Callistus” is situated on the right of the Via Appia, about a quarter of a mile nearer Rome than the Cemetery of S. Sebastian (“ad Catacombas”) just described; the usual entrance being about one and a quarter miles from the Porta S. Sebastiana (Porta Appia).

PAINTING IN A CHAPEL OF CATACOMB OF S. CALLISTUS—SHEWING A TOMB SUBSEQUENTLY EXCAVATED ABOVE THE ORIGINAL TOMB OF THE SAINT