There is still another Rome, the subterranean one, which is well worth study, for we learn more from it about early Christianity than from all the books that have been written. The crypts of the Christian burying-places occupy a zone around the city a couple of miles in width, and embrace about fifty distinct catacombs. Signor Rossi estimates the length of the subterranean passages at 360 miles. They are excavated in the tufa, and are, on an average, a yard in width, but they include chambers which served as oratories, and numerous tiers of niches for the bodies. The inscriptions, bas-reliefs, and paintings of these cities of the dead were at all times respected by the pagans, and fortunately the entrances to them were closed up at the time the Barbarians invaded Rome. This saved their contents from destruction, and everything was found intact when they were first reopened towards the close of the sixteenth century. These tombs prove that the popular belief of the Christians of that time was very different from what it is {278} represented to have been by contemporaneous writers, who belonged to a different class of society from that of the majority of the faithful. A serene gaiety reigns throughout, and lugubrious emblems find no place there. We neither meet with representations of martyrdoms nor with skeletons or images of Death; even the cross, which at a later epoch became the great symbol of Christianity, is not seen there. The most common symbols met with are those of the Good Shepherd carrying a lamb upon his shoulders, and the vine decked with leaves. In the oldest catacombs, which date back to the second and third centuries, the figures are Greek in character, and abound in heathen subjects. One represents the Good Shepherd surrounded by the Three Graces. There are two Jewish catacombs, likewise excavated in the tufa, and they enable us to compare the religious notions which prevailed at that time amongst the followers of the two religions. [Illustration: Fig. 101.—THE HILLS OF ROME.] By an absurd predilection for mystical numbers, Rome is even now spoken of as the “City of the Seven Hills,” although it lost all claim to such a designation {279} after it had outgrown the walls built by Servius Tullius. Independently of Monte Testaccio, which is merely a heap of potsherds, there are at least nine hills within the walls of actual Rome, viz. the Aventino, to which the plebeians retired during their feeble struggles for independence; the Palatino, the ancient seat of the Cæsars; the Capitolino, surmounted by the temple of Jupiter; Monte Celio (Cælius); the Esquilino; Viminale; Quirinale; Citorio; and the Pincio, with its public gardens. Besides these, there are two hills on the opposite bank of the Tiber, viz. Monte Gianicolo (Janiculum), the highest of all, and the Vatican, which derives its name from the Latin word _vates_, a soothsayer, it having once been the seat of Etruscan divination.