In the year 1849 De Rossi found in a cellar in this vineyard a broken marble slab with the mutilated inscription ELIVS · MARTYR, and at the beginning the upper part of the letters RN. He immediately conjectured that this was a fragment of the tombstone of Cornelius, a Roman bishop of the third century, whose sepulchre would probably be found not far off. At his persuasion the pope purchased the vineyard, and the archæological commission began the work of excavation. They were rewarded by some of the most remarkable discoveries which have yet been made. The cemetery is situated between the Via Appia and the Via Ardeatina, which are connected by narrow cross-roads. De Rossi has prepared a map of the principal part of it, divided into fifteen rectilinear and generally rectangular areas. The dimensions of these areas are not fractional but round numbers, as 100, 125, 150, and 250 feet, which cannot be the result of accident, and, with other evidences, indicate that they were, like similar pagan sepulchral areas, originally so many separate places of burial. When brought under the ecclesiastical control of Callixtus, about A. D. 200, they probably received one common name, became structurally united, and were used as a public cemetery of the church. The first of these areas which we reach on entering the vineyard is that known as the crypt of St. Lucina. It has a frontage of one hundred feet on the Via Appia, and an extension _in agro_ of two hundred and thirty feet. The limits of this area are exactly defined by the presence of a small pagan _hypogæum_ on each side, which the Christians dared not undermine. In the centre, near the road, is 169 a massive monument, shown in the section of this crypt, Fig. 14, which De Rossi conjectures to have been a Christian mausoleum,[297] quoting Tertullian[298] as a witness that they had _monumenta et mausolea_ at a very early period.[299] This is more probable from the fact that the property belonged to the noble Roman family of the Cæcilii, with which Cicero was connected, many of whose tombs were found in the neighbourhood. This probably explains its vicinity to the stately mausoleum of Cæcilia Metella. The names of many Cæcilii and other noble Roman families are also found on epitaphs in this crypt. This was unquestionably one of the most ancient areas of the Catacombs. In this area, in 1852, the remaining portion of the epitaph of Cornelius was found at the foot of the tomb to which it evidently belonged, in a gallery of unusual width.