And with this is connected one of the most important historic facts with regard to the Art of the catacombs. In no one of the pictures of the earlier centuries is support or corroboration to be found of the distinctive dogmas and peculiar claims of the Roman Church. We have already spoken of the pictures that have been supposed to have symbolic reference to the doctrine of the Real Presence in the Eucharist, and have shown how little they require such an interpretation. The exaltation of St. Peter above the other Apostles is utterly unknown in the works of the first three centuries; in instances in which he is represented, it is as the companion of St. Paul. The Virgin never appears as the subject of any special reverence. Sometimes, as in pictures of the Magi bringing their gifts, she is seen with the child Jesus upon her lap. No attempt to represent the Trinity (an irreverence which did not become familiar till centuries later) exists in the catacombs, and no sign of the existence of the doctrine of the Trinity is to be met with in them, unless in works of a very late period. Of the doctrines of Purgatory and Hell, of Indulgences, of Absolution, no trace is to be found. Of the worship of the saints there are few signs before the fourth century,--and it was not until after this period that figures of the saints, such as those spoken of heretofore, in the account of the crypt of St. Cecilia, became a common adornment of the sepulchral walls. The use of the _nimbus_, or glory round the head, was not introduced into Christian Art before the end of the fourth century. It was borrowed from Paganism, and was adopted, with many other ideas and forms of representation, from the same source, after Romanism had taken the place of Paganism as the religion of the Western Empire. The faith of the catacombs of the first three centuries was Christianity, not Romanism.