Hardly any distinction can be set up in the material contents of the art; it was at least for a period only simplified and sweetened, and it is this freshening which prepared the way for future development. It must be confessed, however, that certain influences darkened the style even before it had reached maturity; chief among these was a gloomy hierarchical splendour, and a ritual rigidity, which to-day we yet refer to, quite properly, as Byzantinism. Choisy sees a distinction in the constructive types of Roman and Byzantine architecture, in that the former covered spaces by concreted vaults built on centres, which approximated to a sort of "monolithic" formation, whereas in the Byzantine style the vaults were built of brick and drawn forward in space without the help of preparatory support. Building in this way, it became of the greatest importance that the vaults should be so arranged as to bring about an equilibrium of thrusts. The distinction holds as between Rome in the 4th century and Constantinople in the 6th, but we are not sufficiently sure that the concreted construction did not depend on merely local circumstances, and it is possible, in other centres of the empire where strong cement was not so readily obtainable, and wood was scarce, that the Byzantine constructive method was already known in classical times. Choisy, following Dieulafoy, would derive the Byzantine system of construction from Persia, but this proposition seems to depend on a mistaken chronology of the monuments as shown by Perrot and Chipiez in their History of Art in Persia. It seems probable that the erection of brick vaulting was indigenous in Egypt as a building method. Strzygowski, in his recent elaborate examination of the art-types found at the palace of Mashita (Mschatta), a remarkable ruin discovered by Canon Tristram in Moab, of which the most important parts have now been brought to the new Kaiser Friedrich Museum in Berlin, shows that there are Persian ideas intermixed with Byzantine in its decoration, and there are also brick arches of high elliptical form in the structure. He seems disposed to date this work rather in the 5th than in the 6th century, and to see in it an intermediate step between the Byzantine work of the west and a Mesopotamian style, which he postulates as probably having its centre at Seleucia-Ctesiphon. From the examples brought forward by the learned author himself, it is safer as yet to look on the work as in the main Byzantine, with many Egyptian and Syrian elements, and an admixture, as has been said, of Persian ideas in the ornamentation. Egypt was certainly an important centre in the development of the Byzantine style.
The course of the transition to Byzantine, the first mature Christian style, cannot be satisfactorily traced while, guided by Roman archaeologists, we continue to regard Rome as a source of Christian art apart from the rest of the world. Christianity itself was not of Rome, it was an eastern leaven in Roman society. Christian art even in that capital was, we may say, an eastern leaven in Roman art. If we set the year 450 for the beginning of Byzantine art, counting all that went before as early Christian, we get one thousand years to the Moslem conquest of Constantinople (1453). This millennium is broken into three well-marked periods by the great iconoclastic schism (726-842) and the taking of Constantinople by the Crusaders in 1204. The first we may call the classical epoch of Byzantine art; it includes the mature period under Justinian (the central year of which we may put as 550), from which it declined until the settlement of the quarrel about images, 400 years in all, to, say, 850. The second period, to which we may assign the limits 850-1200, is, in the main, one of orientalizing influences, especially in architecture, although in MSS. and paintings there was, at one time, a distinct and successful classical revival. The interregnum had caused almost complete isolation from the West, and inspiration was only to be found either by casting back on its own course, or by borrowing from the East. This period is best represented by the splendid works undertaken by Basil the Macedonian (867-886) and his immediate successors, in the imperial palace, Constantinople. The third period is marked by the return of western influence, of which the chief agency was probably the establishment of Cistercian monasteries. This western influence, although it may be traced here and there, was not sufficient, however, to change the essentially oriental character of the art, which from first to last may be described as Oriental-Christian.
Architecture.—The architecture of our period is treated in some detail in the article Architecture; here we can only glance at some broad aspects of its development. As early as the building of Constantine's churches in Palestine there were two chief types of plan in use—the basilican, or axial, type, represented by the basilica at the Holy Sepulchre, and the circular, or central, type, represented by the great octagonal church once at Antioch. Those of the latter type we must suppose were nearly always vaulted, for a central dome would seem to furnish their very raison d'être. The central space was sometimes surrounded by a very thick wall, in which deep recesses, to the interior, were formed, as at the noble church of St George, Salonica (5th century?), or by a vaulted aisle, as at Sta Costanza, Rome (4th century); or annexes were thrown out from the central space in such a way as to form a cross, in which these additions helped to counterpoise the central vault, as at the mausoleum of Galla Placidia, Ravenna (5th century). The most famous church of this type was that of the Holy Apostles, Constantinople. Vaults appear to have been early applied to the basilican type of plan; for instance, at St Irene, Constantinople (6th century), the long body of the church is covered by two domes.
At St Sergius, Constantinople, and San Vitale, Ravenna, churches of the central type, the space under the dome was enlarged by having apsidal additions made to the octagon. Finally, at St Sophia (6th century) a combination was made which is perhaps the most remarkable piece of planning ever contrived. A central space of 100 ft. square is increased to 200 ft. in length by adding two hemicycles to it to the east and the west; these are again extended by pushing out three minor apses eastward, and two others, one on either side of a straight extension, to the west. This unbroken area, about 260 ft. long, the larger part of which is over 100 ft. wide, is entirely covered by a system of domical surfaces. Above the conchs of the small apses rise the two great semi-domes which cover the hemicycles, and between these bursts out the vast dome over the central square. On the two sides, to the north and south of the dome, it is supported by vaulted aisles in two storeys which bring the exterior form to a general square. At the Holy Apostles (6th century) five domes were applied to a cruciform plan, that in the midst being the highest. After the 6th century there were no churches built which in any way competed in scale with these great works of Justinian, and the plans more or less tended to approximate to one type. The central area covered by the dome was included in a considerably larger square, of which the four divisions, to the east, west, north and south, were carried up higher in the vaulting and roof system than the four corners, forming in this way a sort of nave
and transepts. Sometimes the central space was square, sometimes octagonal, or at least there were eight piers supporting the dome instead of four, and the "nave" and "transepts" were narrower in proportion. If we draw a square and divide each side into three so that the middle parts are greater than the others, and then divide the area into nine from these points, we approximate to the typical setting out of a plan of this time. Now add three apses on the east side opening from the three divisions, and opposite to the west put a narrow entrance porch running right across the front. Still in front put a square court. The court is the atrium and usually has a fountain in the middle under a canopy resting on pillars. The entrance porch is the narthex. The central area covered by the dome is the solea, the place for the choir of singers. Here also stood the ambo. Across the eastern side of the central square was a screen which divided off the bema, where the altar was situated, from the body of the church; this screen, bearing images, is the iconastasis. The altar was protected by a canopy or ciborium resting on pillars. Rows of rising seats around the curve of the apse with the patriarch's throne at the middle eastern point formed the synthronon. The two smaller compartments and apses at the sides of the bema were sacristies, the diaconicon and prothesis. The continuous influence from the East is strangely shown in the fashion of decorating external brick walls of churches built about the 12th century, in which bricks roughly carved into form are set up so as to make bands of ornamentation which it is quite clear are imitated from Cufic writing. This fashion was associated with the disposition of the exterior brick and stone work generally into many varieties of pattern, zig-zags, key-patterns, &c.; and, as similar decoration is found in many Persian buildings, it is probable that this custom also was derived from the East. The domes and vaults to the exterior were covered with lead or with tiling of the Roman variety. The window and door frames were of marble. The interior surfaces were adorned all over by mosaics or paintings in the higher parts of the edifice, and below with incrustations of marble slabs, which were frequently of very beautiful varieties, and disposed so that, although in one surface, the colouring formed a series of large panels. The choicer marbles were opened out so that the two surfaces produced by the division formed a symmetrical pattern resembling somewhat the marking of skins of beasts.
Mosaics and Paintings.—The method of depicting designs by bringing together morsels of variously colored materials is of high antiquity. We are apt to think of a line of distinction between classical and Christian mosaics in that the former were generally of marble and the latter mostly of colored and gilt glass. But glass mosaics were already in use in the Augustan age, and the use of gilt tesserae goes back to the 1st or 2nd century. The first application of glass to this purpose seems to have been made in Egypt, the great glass-working centre of antiquity, and the gilding of tesserae may with probability be traced to the same source, whence, it is generally agreed, most of the gilt glass vessels, of which so many have been found in the catacombs, were derived. The earliest existing mosaics of a typically Christian character are some to be found at Santa Costanza, Rome (4th century). Other mosaics on the vaults of the same church are of marble and follow a classical tradition. It is probable that we have here the meeting-point of two art-currents, the indigenous and the eastern. In Rome, the great apse-mosaic of S. Pudenziana dates from about A.D. 400. The mausoleum of Galla Placidia, Ravenna, is incrusted within by mosaic work of the 5th century, and most probably the dome mosaics of the church of St George, Salonica, are also of this period. Of the 6th century are many of the magnificent examples still remaining at Ravenna, portions of the original incrustation of St Sophia, Constantinople, those of the basilica at Parenzo, on the Gulf of Istria, and of St Catherines, Sinai. An interesting mosaic which is probably of this period, and has only recently been described, is at the small church of Keti in Cyprus. This, which may be the only Byzantine mosaic in the British dominions, fills the conch of a tiny apse, but is none the less of great dignity. In the centre is a figure of the Virgin with the Holy Child in her arms standing between two angels who hold disks marked with the sign Χ. They are named Michael and Gabriel. Another mosaic of this period brought from Ravenna to Germany two generations ago has been recently almost rediscovered, and set up in the new Museum of Decorative Art in Berlin. In this, a somewhat similar composition fills the conch of the apse, but here it is the Risen Christ who stands between the two archangels. Above, in a broad strip, a frieze of angels blowing trumpets stand on the celestial sea on either hand of the Enthroned Majesty.
Such mosaics flowed out widely over the Christian world trom its art centres, as far east as Sanâ, the capital of Yemen, as far north as Kiev in Russia, and Aachen in Germany, and as far west as Paris, and continued in time for a thousand years without break in the tradition save by the iconoclastic dispute. The finest late example is the well-known "mosaic-church" (the Convent of the Saviour) at Constantinople, a work of the 14th century.
The single figures were from the first, and for the most part, treated with an axial symmetry. Almost all are full front; only occasionally will one, like the announcing angel, be drawn with a three-quarter face. The features are thus kept together on the general map of the face. In the same way the details of a tree will be collected on a simple including form which makes a sort of mat for them. Groups, similarly, are closely gathered up into masses of balanced form, and such masses are arranged with strict regard for general symmetry. "The art," as Bayet says, "in losing something of life and liberty became so much the better fitted for the decoration of great edifices." The technical means were just as much simplified, and only a few frank colours were made sufficient, by skilful juxtaposition, to do all that was required of them. The fine pure blue, or bright gold, backgrounds on which the figures were spaced, as well as the broken surface incidental to the process, created an atmosphere which harmonized all together. At St Sophia there were literally acres of such mosaics, and they seem to have been applied with similar profusion in the imperial palace.
Mosaic was only a more magnificent kind of painting, and painted design followed exactly the same laws; the difference is in the splendour of effect and in the solidity and depth of colour. Paintings, from the first, must have been of more grey and pearly hues. A large side chapel at the mosaic church at Constantinople is painted, and it is difficult to say which is really the more beautiful, the deep splendour of the one, or the tender yet gay colour of the other. The greatest thing in Byzantine art was this picturing of the interiors of entire buildings with a series of mosaics or paintings, filling the wall space, vaults and domes with a connected story. The typical character of the personages and scenes, the elimination of non-essentials, and the continuity of the tradition, brought about an intensity of expression such as may nowhere else be found. It is part of the limited greatness of this side of Byzantine art that there was no room in it for the gaiety and humour of the later medieval schools; all was solemn, epical, cosmic. When such stories are displayed on the golden ground of arches and domes, and related in a connected cycle, the result produces, as it was intended to produce, a sense of the universal and eternal. Beside this great power of co-ordination possessed by Byzantine artists, they created imaginative types of the highest perfection. They clothed Christian ideas with forms so worthy, which have become so diffused, and so intimately one with the history, that we are apt to take them for granted, and not to see in them the superb results of Greek intuition and power of expression. Such a type is the Pantocrator,—the Creator-Redeemer, the Judge inflexible and yet compassionate,—who is depicted at the zenith of all greater domes; such the Virgin with the Holy Child, enthroned or standing in the conchs of apses, all tenderness and dignity, or with arms extended, all solicitude; of her image the Painter's Guide directs that it is to be painted with the "complexion the colour of wheat, hair and eyes brown, grand eyebrows, and beautiful eyes, clad in beautiful clothing, humble, beautiful and faultless"; such are the angels with their mighty
wings, splendid impersonations of beneficent power; such are the prophets, doctors, martyrs, saints,—all have been fixed into final types.