The vagueness with which writers on Art have treated the Byzantine and Romanesque styles of Architecture, even to within the last few years, has extended itself also to their concomitant decoration. This vagueness has arisen chiefly from the want of examples to which the writer could refer; nor was it until the publication of Herr Salzenberg's great work on Sta. Sofia at Constantinople, that we could obtain any complete and definite idea of what constituted pure Byzantine ornament. San Vitale at Ravenna, though thoroughly Byzantine as to its architecture, still afforded us but a very incomplete notion of Byzantine ornamentation: San Marco at Venice represented but a phase of the Byzantine school; and the Cathedral of Monreale, and other examples of the same style in Sicily, served only to show the influence, but hardly to illustrate the true nature, of pure Byzantine art: fully to understand that, we required what the ravages of time and the whitewash of the Mahommedan had deprived us of, namely, a Byzantine building on a grand scale, executed during the best period of the Byzantine epoch. Such an invaluable source of information has been opened to us through the enlightenment of the present Sultan, and been made public to the world by the liberality of the Prussian Government; and we recommend all those who desire to have a graphic idea of what Byzantine decorative art truly was, to study Herr Salzenberg's beautiful work on the churches and buildings of ancient Byzantium.
In no branch of art, probably, is the observation, ex nihilo nihil fit, more applicable than in, decorative art. Thus, in the Byzantine style, we perceive that various schools have combined to form its peculiar characteristics, and we shall proceed to point out briefly what were the principal formative causes.
Even before the transfer of the seat of the Roman Empire from Rome to Byzantium, at the commencement of the fourth century, we see all the arts in a state either of decline or transformation. Certain as it is that Rome had given her peculiar style of art to the numerous foreign peoples ranged beneath her sway, it is no less certain that the hybrid art of her provinces had powerfully reacted on the centre of civilisation; and even at the close of the third century had materially affected that lavish style of decoration which characterised the magnificent baths and other public buildings of Rome. The necessity which Constantine found himself under, when newly settled in Byzantium, of employing Oriental artists and workmen, wrought a still more vital and marked change in the traditional style; and there can be little doubt but that each surrounding nation aided in giving its impress to the newly-formed school, according to the state of its civilisation and its capacity for Art, until at last the motley mass became fused into one systematic whole during the long and (for Art) prosperous reign of the first Justinian.
In this result we cannot fail to be struck with the important influence exercised by the great temples and theatres built in Asia Minor during the rule of the Coesars; in these we already see the tendency to elliptical curved outlines, acute-pointed leaves, and thin continuous foliage without the springing-ball and flower, which characterise Byzantine ornament. On the frieze of the theatre at Patara (a), and at the Temple of Venus at Aphrodisias (Caria), are to be seen examples of flowing foliage such as we allude to. On the doorway of the temple erected by the native rulers of Galatia at Ancyra (b), in honour of Augustus, is a still more characteristic type, and the pilaster capital of a small temple at Patara (c), inscribed by Texier to the first century of the Christian era, is almost identical with one drawn by Salzenberg at Smyrna (d), which he believes to be of the first part of Justinian's reign, or about the year 525 A.D.
In the absence of authentic dates we cannot decide satisfactorily how far Persia influenced the Byzantine style, but it is certain that Persian workmen and artists were much employed at Byzantium; and in the remarkable monuments at Tak-i-Bostan, Bi-Sutoun, and Tak-i-Ghero, and in several ancient capitals at Ispahan-aiven in Flandin and Coste's great work on Persia we are struck at once with their thoroughly Byzantine character; but we are inclined to believe that they are posterior, or at most contemporaneous, with the best period of Byzantine art, that is, of the sixth century. However that may be, we find the forms of a still earlier period reproduced so late as the year 363 A.D.; and in Jovian's column at Ancyra (e), erected during or shortly after his retreat with Julian's army from their Persian expedition, we recognise an application of one of the most general ornamental forms of ancient Persepolis. At Persepolis also are to be seen the pointed and channelled leaves so characteristic of Byzantine work, as seen d in the accompanying example from Sta. Sofia (f); and at a later period, i.e. during the rule of the Caesars, we remark at the Doric temple of Kangovar (g) contours of moulding precisely similar to those affected in the Byzantine style.