Mohammedan architecture of India developed under the Moguls a tremendous skill in an elaborate marble mosaic of opus sectile type in which the most intricate curvilinear patterns are formed in the cut marble, and colour is furnished by the rich use of precious and semi-precious stones, as well as coloured marbles and enamel.
Another characteristically Mohammedan development is that of small scale geometric mosaic in wood, for the decoration of furniture, boxes and implements. This art was especially prac tised in Cairo, Damascus and north India and persists in parts of the Mohammedan world to the present day. Frequently ivory and mother-of-pearl are combined with different coloured woods in the patterns. A similar technique is employed to-day in parts of Italy. No definite line can be drawn between wood mosaic of this type and that which is known as marquetry (q.v.). Similarly the quasi-mosaic work in wood inlays, known as intarsia, of which the most remarkable example is the choir stalls of the church of S. Pietro Casinensi, at Perugia, from designs said to be by Raphael, executed by Stefano da Bergamo (1535), is more truly marquetry than mosaic.
the coming of the Renaissance, mosaic art almost completely disappeared, and where mosaic was used by Renaissance decorators, such as the work of Titian in St. Mark's at Venice, it was merely an attempt to imitate painting. Only in Venice, in the form of jewellery and similar small work, did the vitality of the art continue. There, at least in technique, it seems to have persisted down to modern times, although in design fol lowing the fashion of the day. It was not until the revivals of the 19th century that mosaic art resumed any importance what soever as mural decoration. The tendency toward decorative lavishness, so characteristic of the Gothic revival, was peculiarly fruitful in resurrecting the art. Almost all of the middle 19th cen tury work is Venetian, and much of it produced by Antonio Salviati. The mosaics of the central hall of the houses of par liament, at Westminster, from designs by Sir Edward Poynter, and those of the reredos of Westminster abbey (1867) are typical. They show the great fault common in these revival mosaics— a surface polished smooth, tesserae so close together that joints between them become almost invisible, and design which neglects the material and aims principally at pictorial effect. Even in the
much more successful mosaics from the designs of Sir Edward Burne-Jones, in the American church at Rome, the surface is too smooth to bring out the maximum decorative effect. Similarly, in France, the mosaics of the ceiling of the Escalier Daru, by Lenepveu, the apses of the Madeleine by Gilbert Martin and the Pantheon, by Hebert, show the same fault of texture, though in design revealing the customary brilliance of French mural deco ration. During the present century the decorative possibilities, as well as the limitations of the material have come to be more thoroughly recognized, and work as different as that of the Gig gleswick school chapel in England, by Sir T. G. Jackson, and the extremely modernist Golden hall in the town hall of Stock holm, by Ragnar Ostberg, alike show a true grasp of the necessity of keeping surfaces rough, drawing simply and allowing the ce ment in the joints between the tesserae to count as part of the decorative effect.
In the making of the best modern mosaic two general methods are employed. In one, the tesserae are fixed in place by hand, on the wall or vault itself. This is, undoubtedly, the most direct method, and allows the light on each piece to be studied in place. The more common technique is to prepare an outline drawing on heavy paper, which is the reverse of the full size cartoon for the design. Upon this the tesserae are glued in place. When this process is completed, the paper is cut into pieces small enough to be handled easily. The wall to be decorated has in the mean while been brought to a perfect surface with a special cement. Fresh cement is placed over this surface, and into it are pressed the tesserae with their faces still glued to the original drawing; when the cement has sufficiently set, the paper is torn off, the joints pointed with cement and the whole cleaned. This method allows the choice of the tesserae and their arrangement to be accomplished at leisure in a studio. If carefully handled with the necessary changes, when the tesserae are in place, slight errors may be satisfactorily corrected, although certain critics maintain that the best results can only be obtained by the direct application of the tesserae to the wall. In recent years new effects have been obtained by leaving the background entirely in cement, only the figure, or pattern itself being in mosaic.
Another strictly modern development of mosaic has resulted from the use of small tiles for floors, wherever ease of cleaning is imperative. Thus mosaics of small, vitrified tile, in uniform shapes—especially squares, hexagons and circles, or of small rectangles arranged in a basket weave design—are common, not only in the halls of tenement houses, public buildings, etc., but also on the floors and as wainscoting in baths, toilet rooms, lava tories, swimming pools and even kitchens.
Modern decorative mosaic floors are largely based on the opus sectile of Roman imperial work, and especially in churches, upon those combinations of opus sectile and opus Alexandrinum so characteristic of mediaeval Italy.
(See, also, AMBO, APSE, BASILICA, BYZANTINE AND ROMANESQUE ARCHITECTURE, GLASS, MARQUETRY.)