The sketch will deal with each of the “Viæ” or public roads leading out of Rome, in the immediate neighbourhood of which the different cemeteries or Catacombs have been excavated,--each public road having its own special group of cemeteries, lying hard by beneath the vineyards or gardens abutting on the road. THE VATICAN HILL Naturally, the cemetery on the Vatican Hill, which includes the tomb of S. Peter, must be mentioned first. The whole district of the Vatican in the days of Nero (middle years of the first century of the Christian era) was covered with gardens and villas; it communicated directly with the city by means of the Pons Triumphalis, afterwards termed the Pons Neronianus, and was traversed by the Via Triumphalis and the Via Cornelia. Between these two roads the Apostle S. Peter was buried. The Pilgrim Itineraries describe the sacred tomb now as “juxta viam Corneliam”--now as “juxta viam Triumphalem.” Directly over the apostle’s tomb[124] Anacletus, the Bishop of Rome, third in succession, erected a “Memoria” or little chapel. This “Memoria” or Chapel of Anacletus grew into the lordly basilica known subsequently as S. Peter’s at Rome. The tomb in question is situated close by the spot where without doubt the apostle suffered martyrdom in the year of grace 67. Around the tomb of S. Peter, as we shall see, were buried the nine or ten first Bishops or Popes of Rome, as well as other nameless saints once famous in the early years of the story of the Roman congregations. It is doubtful if there was ever a Catacomb, as we understand the term, on the Vatican Hill. No trace of subterranean corridors, or of chambers leading out of the corridors, have been found; only, it must be remembered that the neighbourhood of the tomb of S. Peter and the early Bishops of Rome has been completely changed owing to the excavations necessary for the foundations of the great basilica erected over the little Memoria of Anacletus by Constantine the Great in the first half of the fourth century. THE VIA AURELIA The Via Aurelia Vetus was probably originally laid out by C. Aurelius, Censor in the year of grace 512. It started from the Janiculum (the modern Gate of S. Pancras) and led directly towards the sea-board. It was the road from Rome to Centumcellæ (Civita Vecchia). The cemeteries along the Via Aurelia have been as yet very imperfectly explored.[125] The ancient Pilgrim Itineraries mention four distinct cemeteries here. (1) That of SS. Processus and Martinianus, first century. (2) S. Calepodius or S. Callistus, third century. (3) S. Pancratius, fourth century. (4) The two Felixes, fourth century.