And so the Emperor sets out on the campaign from which he has reason to think that he may never return. The pageantry of his departure, the magnificent armour that he wears, are in strange contrast to the face of Aurelius, “with its habitually dejected hue grown now to an expression of positive suffering.” He departs, and Marius returns to his musings; but in a lonely ride into the Sabine Hills he has a strange uplifting of spirit, in which he feels that behind all the complexity of life, “behind the veil of a mechanical and material order, but only just behind it,” there moves a guide, a heavenly friend, ever at his side, to whom he is perhaps dearer than even to himself, a Father of Men. Marius felt that after the realisation of this possibility, his life could never be quite the same again, and that only in the light of this hope could he apprehend the secret of the lonely pilgrimage upon which he seemed to be bound. Some time is now supposed to elapse, and in the fourth part Marius comes upon the scene again at a banquet at which the young Commodus is present, and also the great Apuleius, with whom Marius has a few moments of private conversation. Apuleius unfolds to his companion his belief in a kind of middle order of beings, between man and God, by whom the prayers and aspirations of humanity can be carried and interpreted to God. It is, indeed, the doctrine of the ministry of angels which is thus foreshadowed; and the effect on Marius is to give a heightened sense of unreality to the world in which he moves; and it is at this juncture that he visits with Cornelius the villa of Cecilia, and is deeply impressed with the order, the industry, the joyful peace of the household. Cornelius takes his friend through a garden and into the old catacomb of the Cecilii, where Marius sees the graves of Christians, and reads with a strange thrill of spirit the touching and inspiring inscriptions on their tombs, that seem to exorcise the terrors of death by a serene and lively hope. The fresh and cool sensation of peace with which the whole surroundings are invested is to Marius like a window opened from a hot and fragrant room into the dawn of some other morning. Here, he fancied, might be the cure, the anodyne for the deep sorrowfulness of spirit under which he seemed to have been always labouring. He began to discern the source of that untroubled serenity, that quiet happiness of which he had always been conscious in his friend. The Christian ideal of that period, during the peace of the Antonines, had lent itself to the harmonious development of human nature, in a due proportion, rather than to the idea of ascetic self-sacrifice; and the divine urbanity and moderation of this secluded household exercised a strong spell over the sensuous temperament of Marius.