[Illustration: FIG. 13.9 Vatican City, excavations under St. Peter’s, Campo P. (Toynbee and Ward Perkins, _op. cit._, p. 141)] But this is not the end of the problem. The next question is, “How early can the burial, by objective archaeological evidence, be demonstrated to be?” The answer to this question must be sought, if anywhere, in the context of Campo P. This proved on excavation to be an area of poor graves, marked, like those of the necropolis of the Port of Ostia on Isola Sacra, simply by a surround and a pitched roof of tiles, without any of the pomp of costly marble sarcophagus or richly stuccoed mausoleum. It is to the class which would be buried in such pathetic graves as these that the earliest Roman Christians (of the age of Nero [A.D. 64]) must have belonged. (Since the _Report_ was published, Professor Magi, whom we have already met in connection with the Cancelleria reliefs, has discovered, under the Vatican City parking lot, another cemetery, also of poor graves, of the first century A.D.; there is no cogent proof that they are Christian.) The graves in Campo P (Fig. 13.9) were found to lie at various levels: the deepest must be the earliest. The deepest is the one called by the excavators Gamma (see plan, γ, Fig. 13.9): it lies five-and-a-half feet below the pavement of Campo P, and it partly underlies, and is therefore older than, the foundations of the Red Wall, which in turn is dated by the Clivus drain about the middle of the second century A.D. Grave Theta (θ) is higher, and therefore later, than Gamma. It is a poor grave, protected by tiles, one of which bears a stamp of Vespasian’s reign (A.D. 69–79). It is unsafe method to date an archaeological find by a single brick stamp which could be second-hand, used at any date later than its firing, even much later. But the stamp creates at least a presumption that Theta may be dated as early as A.D. 79, and, if so, Gamma must be earlier still. Since both these graves appear to have been dug in such a way as to respect the area just in front of the Aedicula, it follows that the bones in the lowest niche must be earlier than either grave.