and noble testimony to the faith sealed with their life-blood, of these true servants of the adored Master, is positively established by what has been found in the last fifty years in the Roman city of the Christian dead.
De Rossi and his companions have indeed given us a perfectly new and most striking page in the history of this early Christian Church.
II
It will be of special interest briefly to glance over the principal portion of the materials which De Rossi made use of as his guide during his long forty years' labours in the exploration of the Catacombs. First in order must be taken what may be termed the literature bearing on the City of the Dead.
The most important of these pieces are
1. The Acts of the Martyrs. These have already been alluded to as possessing, save in a few instances, little historic authority, as they were mostly composed two centuries or even more after the events which they purported to relate happened. But they were not without their value to the Catacomb explorers, for it must be remembered that when these "Acts" were put together in the form we now possess them, in the fifth, sixth, and seventh centuries, the Catacombs were still an object of eager pilgrimage from all lands, and many of the details in these "Acts" evidently were based on an historical tradition, such as the place exactly where the martyr of the "Acts" was buried; such a detail, for instance, served as a guide to the explorer. 2. The Martyrology of S. Jerome—a compilation dating from about the middle of the sixth century, but certainly containing memoranda of an earlier date. 3. The (so-called) Liber Pontificalis—a generally reliable and most interesting work, the earlier portion of which has been largely used throughout Western Christendom, certainly since the sixth century. The first part of this work contains biographical notices of the Bishops of Rome from the days of S. Peter to the times of Pope Nicholas, A.D. 807. The earliest redaction of the first Papal notices in the Liber Pontificalis
