I.

Introduction

Mosaic, the art of creating figurative or geometric designs by embedding into cement small pieces of glass, stone, terracotta, or other suitable materials. Mosaic decoration is best suited to large plane surfaces; it is particularly effective on floors, interior and outside walls, vaults, and ceilings, but can also be applied to small panels and other portable objects. Mosaic was an art form especially well developed by the Romans and used extensively in Byzantine buildings and in Italian churches. Because the materials used in mosaics are relatively resistant to deterioration, many ancient mosaics have survived, and retain the same brilliance today that they had when they were originally laid.

II.

Materials and Techniques

Mosaics in their classic form were made from small pebbles and later of cube-like pieces of marble, hard stone, glass, or terracotta, known as tesserae (Latin, dice).

To make tesserae, thin slabs of marble or of coloured stone were cut into strips, which were then cut or broken into cubes. Molten glass, which could be tinted in a range of colours by the addition of metal oxides, was poured out on to a flat surface to cool and harden. The resulting slab of coloured glass was scored with a sharp tool and broken into strips and cubes. Gold and silver cubes were made by applying gold or silver leaf to slabs of glass in pale shades. The surface was then covered with a frit (a thin layer of powdered glass) and heated in a furnace to seal the gold or silver between the layers of glass; the slab was then scored and broken into cubes.

Different styles of mosaic include opus tesselatum, simple geometric patterns; opus vermiculatum, small stones arranged in patterns of curved lines, or depicting people, animals, plants, or objects; opus musivum, mosaic on the wall in a house; and opus sectile, a pattern composed of larger stones of varied shapes.

Knowledge of ancient mosaic techniques is derived mostly from direct examination of specific examples; damaged mosaics in İstanbul provide explicit information. Walls to be covered with mosaics received a triple coat of plaster. The first layer (a mixture of lime, sand, and brick dust) was applied over the masonry to give a smooth surface. The intermediate layer (of lime, sand, and chopped straw), 1.25 to 5 cm (0.5 to 2 in) thick, was then applied, and was scratched or tooled to receive the third coat, called intonaco, of plaster of lime and marble dust, which was spread over a small area at a time; as much as could be completed in one day, for instance. It was then painted in detail in true fresco and immediately set with coloured tesserae to match the painted surface.

The tesserae were set into the painted intonaco one at a time, with resulting deliberate irregularities of the surface. These variations in surface planes catch the light and impart vitality to the finished wall. In many instances the tesserae are angled downwards in rows, with space between the rows; when viewed from a distance this gives the appearance of a continuous background.

III.

Pre-Christian Mosaics

In Mesopotamia in the 4th to 3rd millennia bc, there developed a type of mosaic composed of slender cones of baked clay. The base ends of some of the cones were painted red, black, and white. The cones were embedded in mud brick walls to create a decorative and protective coating in geometric patterns, perhaps derived from textiles or matting. A large section of a Sumerian wall of half-columns (early 3rd millennium bc) from Erech (Uruk), decorated with these patterns, is preserved in the Staatliche Museen, West Berlin. See Mesopotamian Art and Architecture.

In Crete and on the Greek mainland in the Bronze Age (1600-1000 bc), water-worn pebbles were used to make floor mosaics. Pebble floor mosaics existed throughout the Hellenic Greek world from the 6th to the 4th century bc; notable examples have been discovered in Athens, Corinth, Delphi, Olympia, Olynthus, Pella, Assus, and Tarsus. The polychrome pebble mosaics at Pella in Macedonia, dating from about 300 bc, are excellent examples of the use of subtle variations in the colour of water-polished stones to create beautiful figural compositions, often depicting light figures against a dark background, delineated by either lead or ceramic strips.

Before the end of the 3rd century bc, pebbles were in large part replaced by tesserae cut from stone and sometimes from glass. The smooth surfaces of the tesserae made the mosaic more resistant to wear and tear and also made possible the creation of more detailed designs. Cutting the tesserae to small sizes and packing them closely together, craftsmen were able to create designs of impressive detail, realistically depicting scenes with human figures, animals, plants, and landscapes. See Greek Art and Architecture.

The Romans learnt the art of mosaic from the Greeks, and developed their own mosaic style. Mosaics then spread throughout the Roman Empire. Polychrome scenes of the late 2nd and early 1st centuries bc are among the earliest mosaics at Pompeii. The Alexander mosaic from the House of the Faun depicts the Battle of Issus and is thought to be a copy of a lost Hellenistic painting of the 4th century bc; the mosaic, however, was most probably executed in the 1st century bc. Mosaics from Antioch (modern Antakya in Turkey) dating from the late 2nd to the 6th century ad show a predilection for polychrome figural mosaics. Mythological themes, including the Judgement of Paris, Narcissus, and the Labours of Hercules, are depicted with great realism and in brilliant colours. See Roman Art and Architecture.

IV.

Christian and Islamic Mosaics

In Early Christian mosaics of the 4th to the 6th century, decorative borders frame human figures, animals and birds, and frequently hunting scenes. In the Church of Santa Costanza in Rome, built about ad 350, the vaults carry mosaics of vine scrolls and geometric designs that enclose figures of pagan origin. See Early Christian Art and Architecture.

A.

Byzantine Mosaics

Mosaics produced in various parts of the Byzantine Empire are among the finest examples of the genre. Early examples of the 5th and 6th centuries are found in cities somewhat removed from the capital city of Constantinople. The mosaics of the 5th and 6th centuries in Ravenna, Italy, are especially well known. They include depictions of the Good Shepherd (5th century) in the Mausoleum of Galla Placidia, the Baptism of Christ in the Jordan (c. 450) in the Orthodox Baptistery, and, most important, the mosaics in the presbytery of the Church of San Vitale, dating from about 547. Flanking the apse, two important imperial processions are depicted, with full-length portraits of Emperor Justinian I and Empress Theodora. The Basilica of Sant' Apollinare in Classe, near Ravenna, consecrated in 549, has a most impressive apse mosaic depicting the Transfiguration of Christ. In the monastery church of St Catherine on Mount Sinai is another fine 6th-century mosaic of the transfiguration.

Byzantine figural mosaics in religious monuments in Constantinople were all destroyed during the iconoclastic period of the 8th and 9th centuries. Some decorative mosaics of preiconoclastic periods remain, however, as well as nonrepresentational decorations of the 8th and 9th centuries, such as the large cross on a gold background in the apse of Hagia Irene (Church of the Holy Peace) next to Hagia Sophia (Church of the Holy Wisdom). Exceptionally fine examples of secular mosaics survive in the remains of the palace of the Byzantine emperors in Constantinople. These huge 6th-century floor mosaics show hunting scenes, domestic activities, and abstract designs, framed with wide rinceau (foliate scroll) borders.

With the restoration of pictorial representations in churches in 843, mosaics depicting figures were again installed in Hagia Sophia. In the south vestibule is a fine mosaic of Justinian I presenting a model of his church to an enthroned Virgin and Child, with Constantine I standing on the right offering a model of the city. In the inner narthex Leo VI is shown prostrating himself before an enthroned Christ (early 10th century). In the gallery are imperial portraits of emperor Alexander (912-913), Empress Zöe with her third husband, Constantine Monomachus (11th century), and Emperor John II with Empress Irene (12th century). Perhaps the most famous of all Byzantine mosaics is the Deëis, a mosaic of monumental size that depicts Christ enthroned between the Virgin Mary and John the Baptist. Facial and figural details are worked out in great detail with tiny cubes of glass and marble in brilliant colours against a gold background. The mosaic dates from the third quarter of the 13th century. Also in İstanbul are a number of extraordinary mosaics in the double narthex (outer and inner porches) of Kariye Djami—also known as St Saviour in the Chora—of the early 14th century. These depict the life of the Virgin Mary and of Christ in a series of magnificent panels in glowing colours. See Byzantine Art and Architecture.

B.

Islamic Mosaics

Islamic artists produced outstanding monuments with mosaics, including the Dome of the Rock in Jerusalem and the Umayyad Great Mosque in Damascus. The Dome of the Rock was built in the late 7th century and is decorated with floral mosaics depicting acanthus leaves, palm trees, cornucopiae, vases, and tree-of-life motifs. The tesserae are set against gold backgrounds in dominant shades of green and blue, with accents of red, silver, grey, mauve, black, and white. The Umayyad Great Mosque in Damascus was finished in the early 8th century. It has mosaics on both the exterior and the interior of the building that depict floral and tree motifs as well as buildings and an imaginary city.

In the 13th century the Seljuk Turks of Asia Minor developed a mosaic technique using glazed tiles. These mosaics are dominated by turquoise blue, yellow, green, and white against a cobalt blue background; they are set in geometric patterns with Arabic inscriptions. See Islamic Art and Architecture.

C.

Norman Mosaics in Sicily

In Palermo, Sicily, the Norman kings in the 12th century installed mosaics in the Duomo (Cathedral), the Cappella Palatina, the Martorana, the Palazzo Reale, and the Palazzo della Zisa. Other Norman mosaics embellish the interior walls of the great churches at Cefalù (1148 and later) and Monreale (1180-1190); in both churches the sanctuary walls are covered with cycles of biblical scenes and, in the apse, powerful figures of Christ and saints in bright-coloured glass and stone against gold backgrounds.

D.

Italian Mosaics

In Venice the mosaics of San Marco cover a wide range of periods—13th century in the right transept, 14th century in the baptistery, and 17th-century Baroque designs throughout the basilica. Rome is rich in mosaics of various periods, including mosaics in the churches of Santa Maria in Trastevere (1130-1143) and the basilicas of San Paolo Fuori le Mura (1218), San Giovanni in Laterano (1291), and Santa Maria Maggiore (1295).

E.

Miniature Mosaics

Portable or miniature mosaics are among the most prized Byzantine objects. Miniature mosaics are composed of extremely small tesserae and are usually set in a wax or wax-resin cement on wooden panels. Two notable examples are an icon of St John Chrysostom and the Massacre of the Forty Martyrs (both 14th century from Constantinople, Dumbarton Oaks Collection, Washington, D.C.).

F.

Late Western Mosaics

In the Renaissance, mosaic workshops were active in Venice and Rome, where the technique imitated that of illusionistic painting on a gigantic scale, such as those (begun 1576) in the dome of St Peter's Basilica in Rome. A revival occurred during the 19th century, when workshops were established in Italy, France, England, and Russia. The work was imitative of earlier illusionistic styles and principally carried out by Italian artisans trained in reproducing paintings in tesserae.

In recent years a number of artists have revitalized mosaic decoration. Outstanding is the decor of the exterior walls of several buildings at University City in Mexico City.

G.

Pre-Columbian Mosaics

The Native Americans of Central America independently developed a mosaic technique for decorating masks, shields, knife handles, earplugs, mirrors, animal figures, and statuettes. Turquoise, bone, and shell were cut into small pieces, polished, and set with a vegetable resin on to a variety of surfaces, usually wood or pottery. Examples of this type of mosaic may be seen at the Museum of Mankind in London, and in museums in Mexico City, Harvard University's Peabody Museum in Cambridge, Massachusetts, and the Museum of the American Indian in New York. See Pre-Columbian Art and Architecture.