In explanation of the fact, which might at first sight cause surprise, that a paper which consists mainly of a description of paintings is not accompanied by reproductions of the pictures themselves, it is necessary to state that the photographs and other methods by which the appearance of the paintings has been, so far as possible, preserved being the property of the Italian authorities, cannot be published until the official account of the excavations has been issued. The present description must be regarded chiefly as a contribution to our knowledge of Byzantine iconography as it was understood and practised at Rome in the eighth century. It may be added that the damaged condition of all but a few of the pictures makes a careful description almost as valuable for iconographical purposes as reproduction, and that their interest consists rather in the choice and treatment of subjects than in their artistic character.

It is a tendency of all great cities to possess two distinct and often independent sets of communications, the one for local, the other for long-distance traffic; and, unless a city has suddenly sprung into being, it will be found that, in order of development, the former precedes and is the germ of the latter. In the case of Rome, we are able to trace with remarkable clearness the successive stages of the development of the road system. The roads which, when this system had attained its perfection, we find radiating in all directions from the city, may be divided into two groups. The first of these, the local roads, take their name from the cities to which they lead; the second, the longdistance roads, from those who were chiefly responsible for their construction. All, however, must have originated as short-distance roads, leading to some town or other, and if we possessed sufficient information as to the spread of the Roman supremacy in Italy, we should be able to trace step by step the development of the long-distance roads from the local ones in every case. For the growth of the road system is intimately connected with the growth of the power of Rome. As soon as we are able to fix approximately the earliest bounds of her territory, we find her enclosed within very narrow limits. Except along the banks of the Tiber, her dominion extended hardly five miles from the city gates.