What was revealed was a pagan Roman cemetery, in some places thirty feet below the floor of the present church. The mausolea were all in use and in good repair when Constantine began his church in A.D. 322: the earliest brick stamp found in the area dates from the reign of Vespasian, A.D. 69–79. The excavations were carried out under conditions comparable in difficulty only to the recovery of the Altar of Peace: the same constant battle with seepage, the same problem of underpinning one structure in order to read the message of another. Under these formidable difficulties, the cemetery was cleared, and archaeologists found the reason why Constantine moved a million cubic feet of earth and went so far as to violate sepulchres to build Old St. Peter’s on just this site. Whatever modern walls it was necessary to build were carefully marked with Pius XII brick-stamps, that future archaeologists might be in no doubt as to which masonry was modern and which ancient. The cemetery may now be visited by small groups with special permission, under the expert guidance of a polyglot archaeologist. The story he has to tell was not published until over ten years after the excavation began, in a massive two-volume _Report_ which stands fifteen and three-quarters inches high, contains 171 text figures and 119 plates, and weighs fourteen pounds. Fortunately its objectivity is as impressive as its bulk. The archaeological evidence is lucidly set forth, and no conclusions are drawn which exceed it.