mosaic, art of arranging colored pieces of marble, glass, tile, wood, or other material to produce a surface ornament.

Ancient Mosaics

In Egypt and Mesopotamia, furniture, small architectural features, and jewelry were occasionally adorned with inset bits of enamel, glass, and colored stone. Early Greek mosaics (5th-4th cent. B.C.) uncovered at Olynthus were worked in small natural pebbles. The use of cut cubes or tesserae was introduced from the East after the Alexandrian conquest. Roman floor mosaics were probably based upon Greek examples, and glass mosaics applied to columns, niches, and fountains can be seen at Pompeii. In Italy and the Roman colonies the floor patterns were produced both by large slabs of marble in contrasting colors (opus sectile) and by small marble tesserae (opus tessellatum). The tessera designs varied from simple geometrical patterns in black and white to huge pictorial arrangements of figures and animals; examples were found in Rome, Pompeii, Antioch and Zeugma (S Turkey), and N Africa.

Early Christian Mosaics

In the early centuries A.D. glass mosaics brought color and decoration to the broad walls of the basilicas. By the 4th cent. the triumphal arch between nave and apse and the walls above the nave arcades received mosaic adornment, while the entire domed apse was lined with a mosaic picture, generally of Jesus surrounded by saints and apostles.

In this period Byzantium (later Constantinople) became the center of the craft, which reached perfection in the 6th cent. Hagia Sophia exhibits glittering gold backgrounds—a special feature of Eastern mosaic art, which later spread to the West. A gold tessera was produced by applying gold leaf to a glass cube and covering it with a thin glass film to protect against tarnishing; for the other tesserae the colors were produced by metallic oxides. The tesserae were set by hand in the damp cement mortar, and the resulting irregularities, causing the facets to reflect at different angles, were an essential factor of effect. In the 5th and 6th cent. Ravenna became the Western center of mosaic art, and the Ravenna masterworks (e.g., the decoration of San Vitale), as well as those in Rome, show the Byzantine characteristics of stylized rigidity in the figures.

Medieval Mosaics

Through the importation of Greek workmen, a revival took place in Italy in the 11th cent. which lasted into the 13th cent., producing the beautiful mural works of Rome, of Saint Mark's Church and Torcello at Venice, and of Palermo, Monreale, and Cefalù in Sicily. Rich medieval marble and mosaic floors with geometric patterns appeared in Italy, Sicily, and the East. In Russia, especially in Kiev, remarkable figural mosaics were set into the walls.

From the 13th cent., mosaic in Italy and Sicily extended to many architectural elements, such as pulpits, bishops' thrones, paschal candlesticks, and the twisted columns of cloisters. These adornments are commonly termed Cosmati work, after the family of Roman artisans especially gifted in their execution. The rise of fresco decoration in the early 14th cent. in Italy superseded mosaic, which then began to deteriorate into mere simulation of painting, although it lingered in Venice, Greece, and Constantinople.

Modern Mosaics

The Gothic revival of the 19th cent. produced some modern attempts, as in Westminster Abbey and the houses of Parliament. In the 20th cent. the medium has been used with truer understanding of techniques, as in the modernist mosaics for the Stockholm town hall. In modern work the ancient system shares favor with a new method of fastening the tesserae with glue upon a paper cartoon drawn in reverse, applying fairly large sections of this into proper position upon the damp mortar, and then washing away the paper after the mortar has hardened and the tesserae have set.

Surface decoration of small coloured components—such as stone, glass, tile, or shell—closely set into an adhesive ground. Mosaic pieces, or tesserae, are usually small squares, triangles, or other regular shapes. Mosaics cannot create the variations of light and shadow that paintings can, but glass tesserae can achieve a greater brilliance, especially those to which gold and silver foil have been applied. This technique was responsible for the great shimmering mosaics of the Byzantine period. The earliest known mosaics date from the 8th century BC and were made of pebbles, a technique refined by the Greeks in the 5th century. The Romans used mosaics widely, particularly for floors. Pre-Columbian Americans favoured mosaics of garnet, turquoise, and mother-of-pearl, which usually encrusted shields, masks, and cult statues.

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