El-Aksah at Jerusalem in the 8th century; at Cairo in rebuilding that of Amrou in the 9th or 10th, in the Azhar and other mosques of that city, and also, I believe, in the old mosque at Kairoan, which was the immediate stepping-stone by which it crossed to Sicily. It was used too in Spain, at Cordova and Granada, before and after its introduction in Sicily, till it became a settled canon of art, and a usual form of Moorish architecture. As such it was used currently in Sicily by the Moors, and in Palermo and elsewhere became so essential a part of the architecture of the day that it was employed as a matter of course in the churches; but it was not introduced by the Normans, nor was it carried by them from Sicily into France, and, except so far as already stated, it had no influence on the arts of France. In fact there is no connection, either ethnographically or architecturally, between the Sicilian pointed arch and the French; and beyond the accident of the broken centre they have nothing in common.
Although, therefore, it can hardly again be used as evidence in the question of the invention of the pointed arch, the architecture of Sicily deserves a better monography than it has yet been made the subject of. It must, however, be written by some one intimately familiar with the Byzantine, Saracenic, and Romanesque styles. To any one so qualified, Sicily will afford the best field in Europe for tracing the influence of race and climate on architecture; for nowhere, owing in a great measure to its insular position, can the facts be more easily traced, or the results more easily observed.
In one other point of view also the style deserves attention, for from it alone can we fairly weigh the merit of the two systems of internal decoration employed during the Middle Ages. By comparing, for instance, the cathedral at Monreale with such a building as the Sainte Chapelle at Paris, we may judge whether polychromy by opaque pictures in mosaic, or by translucent pictures on glass, is the more beautiful mode of decorating the interior of a building. The former have undoubtedly the advantage of durability, and interfere less with the architectural effect, but for beauty and brilliancy of effect I have little doubt that the general verdict would be that the latter have at least hitherto been the most successful mode. On the whole, however, it seems that a higher and purer class of art may be developed out of opaque painting than can ever be obtained from transparencies, and if this is so there can be little doubt as to which we ought now to seek to cultivate. The question has never yet been fairly discussed; and examples sufficiently approximating to one another, either in age of style, are so rare that its determination is not easy For that very reason it is the more desirable that we should make the most of those we have, and try if from them we can settle one of the most important questions which architectural history has left to be determined with reference to our future progress in the art.
