When the appropriate field had been cleared, and all fitting agencies were prepared, the advent of Christianity rendered possible the full development of the human soul, and a corresponding improvement of noble art. The preliminary throes of a heavenly birth transpired under the last decay of paganism, the impressions of which are preserved in the primitive sculptures, mosaics, and illuminations of the yet persecuted church. In the catacombs under Rome are numerous works of the late Augustan period, not to be exceeded in interest by any other remains of past ages. Many entire days may be well spent in that sanctuary of antiquity, where Paganism and Christianity confront each other engaged in mortal conflict. Great numbers of the vestiges of that struggle and auspicious triumph have been taken from the subterranean chapels and tombs, and are now affixed to the walls of the Vatican, where they furnish abundance of enjoyment and reflection to one studious of the great unfoldings of the divine purpose in human progress. These "sermons in stones" are addressed to the heart, not to the head; and possess great value from being the creation of the purest portion of the "catholic and apostolic church" then extant. In all the Lapidarian Gallery, there are no prayers for the dead, nor to the apostles or early saints; and, with the exception of such relics as "eternal sleep," "eternal home," etc., not one expression contrary to the plain sense of Scripture. This is the more remarkable when it is known that the catacombs remained open during half of the fifth century.