It is easy to see too how the funeral celebrations of the liturgy—given this initial idea of intercommunion and intercession among all Christians living and dead—extended the idea of eucharistic sacrifice. How easily the oblation of Christ—the Christian's one offering—became the means of intercessory prayer for all men and all occasions, and gave rise to the requiem mass, the mass for some special grace, the mass of thanksgiving, the mass in commemoration of a saint.
Bold treatment of sacred things belongs naturally to an age when the sentiments of the faith, aspiration and hope, outrun dogma—before unfaithfulness in doctrine urged upon the early Church and its leaders the necessity for stricter definition, or unfaithfulness in life had made it easier to substitute a hard and fast creed for "the weightier matters of the law." The symbolism and inscriptions of the catacombs testify how freely such elements were at work there. Take as an instance the fresco representing Christ on a throne giving a book to Peter, with the legend, Dominus legem dat, "the Lord gives the law." In other examples of this subject Peter is replaced by some simple but faithful disciple—"the Lord gives the law to Alexander—to Valerius." The allusion is to the "tradition of the Gospel" in baptism; it is not hierarchical.
LIBRARY OF THE HOUSE OF DOMITIAN ON THE PALATINE
Painted on a stormy day. The sombre scene of the ruined Library in the Palace of the Flavian Emperors suggests the ruin of classical learning which followed on the introduction of Christianity. The mother of Domitian's two nephews, whom he had intended to designate as his heirs, was martyred as a Christian, and their cousin of the same name—Flavia Domitilla—founded the catacomb of the Flavian House.
The catacombs influenced the Roman Church in another way. There are none but martyrs' names among the liturgic commemorations of the confessors of the faith (whom we now call "saints"); and these names loudly proclaimed in the Canon—in the solemn portion—of the eucharistic services which were held at their graves, not only on the day of deposition but on many other stated days besides, were the nucleus of that long line of "canonised" saints which figures in the modern calendar. When, after the "Peace," churches began to cover the city, the very grave of the confessor became the nucleus of the Christian edifice—that confession or sunk tomb which is the central point of the Roman basilica. And as the liturgy had been celebrated on the stone slab which closed the grave so when churches were built the altar was placed over the confessor's tomb: "I saw under the altar the souls of those that had been slain for the word of God, and for the testimony which they held."
Thus subterranean Rome prepared, as in the hidden working of a mine, not only many affirmations of the faith which was to assert itself in the light and replace the religion of classical Rome, but also the sanctuary of those great basilicas which were to spread over the surface of the city as soon as the Christians, in no real but nevertheless in a highly suggestive sense, "came up from the catacombs." The catacombs are the link between pagan Rome "drunk with the blood of the saints" and the Christian Rome which arose in the imperial city from the ashes of her martyrs. The pagan city on the seven hills as truly sunk into the grave with the bodies of the Roman martyrs as Christian Rome eventually took possession of the same urbs septicollis by carrying her dead into it.