The collections at the Vatican and the Lateran together do not exceed two thousand. Hundreds of others, recovered by more recent excavations, have not yet found a suitable home; many have been left in their original sites. Still it will always remain true that the number actually in existence is quite insignificant when compared with those which have been destroyed or lost. A large proportion, however, even of these have not altogether perished; they were copied, not always with accuracy, yet with praiseworthy diligence, by various scholars, even from the eighth and ninth centuries; and since the invention of printing, similar collections have been, of course, more frequent. We need not enter into any detailed account of these; we will say but a brief word even about De Rossi’s collection, for as yet he has only published the first volume, which contains all the Christian inscriptions of Rome during the first six centuries, whose date is indisputably fixed by the names of the consuls having been appended to them. Of these, only one belongs to the first century, two to the second, the third supplies twenty, and the fourth and fifth about five hundred each. Of this last century, of course, only those which belong to the first ten years can be claimed for the Catacombs, because, as we have already seen, they ceased after that period to be the common cemetery of the faithful. It appears, then, that all the dated inscriptions of gravestones found in the Catacombs up to the year 1864 do not amount to six hundred: whence some writers have argued that in the earliest ages Christians were not in the habit of inscribing epitaphs on their graves. This conclusion, however, is obviously illogical; for we have no right to assume that the proportion between dated and undated inscriptions remained uniform during the first four centuries. If there are only six hundred epitaphs bearing the names of consuls, there are more than twice as many thousands without those names; and we must seek, by independent processes of inquiry, to establish other chronological criteria, which, if not equally exact, may yet be shown to be generally trustworthy. And this is what De Rossi has done, with a zeal tempered by caution which is beyond all praise. It would be impossible to exaggerate, first, the slow and patient industry with which he has accumulated observations; then the care and assiduity with which he compares the innumerable examples he has collected with one another, so as to ascertain their marks of resemblance and difference; and finally, the moderation with which he has drawn his conclusions. These vary in value, from mere conjecture to the highest degree of probability, or even of moral certainty. In a popular work like this, there is no room for discussion; we must confine ourselves to a statement of some of the best ascertained and most important facts, resting upon certain chronological canons, which a daily increasing