I. Introduction

Mosaics, works of art of surface decorations, composed of variously colored small pieces of glass, stone, ceramics, or other materials. Although mosaic decoration is most frequently found on floors and wall and ceiling surfaces, closely set colored components, or tesserae, may also be applied to sculptures, panels, and other objects.

II. Materials and Techniques

In ancient times mosaics were a form of floor decoration made of small pebbles and later of cut or shaped pieces of marble, hard stone, glass, terra cotta, mother-of-pearl, and enamels. The shaped pieces, in the form of small cubes, are called tesserae or tesselae. The tesserae are embedded in plaster, cement, or putty to hold them in place. Techniques for arranging the components in a design include opus tessellatum, simple geometric patterns; opus vermiculatum, small stones arranged in patterns of curved lines, including pictures of objects; opus musivum, mosaic decorations of walls; and opus sectile, a pattern composed of larger stones of varied shapes.

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

To make tesserae, thin slabs of marble or of colored stone were cut into strips, which were then cut or broken into cubes. Molten glass was tinted in a wide range of colors with metal oxides and then poured on a flat surface such as a marble slab to form a disk of colored glass; this was scored with a sharp tool and broken into strips and cubes. Gold and silver cubes were produced by gilding glass slabs of pale shades with gold or silver leaf. The surface was then covered with a frit (thin layer of powdered glass) and reheated in a furnace to secure the gold or silver between the layers of glass; the slab was then scored and broken into small cubes. The cubes 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 backgrounds the cubes are angled downward in rows, with space between the rows; when viewed from a distance this gives the appearance of a solid background. The stone and glass tesserae in mosaics are relatively stable materials, so that many ancient mosaics have survived with the same brilliance that was part of their original conception.

III. Pre-Christian Mosaics

Mesopotamia, in the 4th-3rd millennium bc, developed a type of mosaic composed of slender cones of baked clay with some base ends painted red, black, and white. These were embedded in mud brick walls to create a decorative protective coating in geometric patterns, perhaps derived from textile or matting materials. 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 (Kríti) and on the Greek mainland in the Bronze Age (1600-1000 bc), water-worn pebbles were used to decorate floors. Pebble mosaic floors have been discovered throughout the Hellenic Greek world from the 6th to the 4th century bc, with notable examples in Athens, Corinth, Delphi, Olympia, Olynthus, Pella, Assus, and Tarsus. The polychrome pebble mosaics of about 300 BC at Pella in Macedonia are excellent examples of the use of subtle variations of color in water-polished stones to create beautiful figural compositions, often of light figures against a dark background, with outlines in either lead or ceramic strips.

Before the end of the 3rd century BC, pebbles were in large part replaced with tesserae cut from stone and sometimes from glass. The smooth surfaces of cut cubes proved able to withstand wear and tear and also allowed the artisans to carry out designs in greater detail. The cubes could be cut to small size and packed closely together to create incredible detail, including realistic renditions of naturalistic scenes with human figures, animals, plants, and landscapes. See Greek Art and Architecture.

Mosaics from Pompeii show the introduction of Hellenistic mosaics in Italy. Polychrome scenes of the late 2nd and early 1st centuries BC are among the earliest mosaics at Pompeii. The famous 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. The mosaics from Antioch (modern Antakya in Turkey) on the Orontes River date from the late 2nd into the 6th century AD. They show a predilection for polychrome figural mosaics. Mythological scenes are depicted with great realism in brilliant colors, including a Judgment of Paris, Narcissus, and the Labors of Hercules. 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 ad350, 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 extant. Early examples of the 5th and 6th centuries are found in cities somewhat removed from the capital city of Constantinople (present-day Istanbul). The mosaics of the 5th and 6th centuries in Ravenna, Italy, are especially well known. They include the Good Shepherd (5th century) in the Tomb of Galla Placidia, the Baptism of Christ in the Jordan (circa 450) in the Baptistery of the Orthodox, 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, the Transfiguration of Christ. In the monastery church of Saint 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). Also extant are exceptionally fine examples of secular mosaics 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 restoration of pictorial representations in churches in 843, mosaics with 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 (912-13), Empress ZÃe with her third husband, Constantine Monomachus (11th cent.), and Emperor John II with Empress Irene (12th cent.). Perhaps the most famous of all Byzantine mosaics is the DeÃxis, a mosaic of monumental size that depicts Christ enthroned between the figures of 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 colors against a gold background. The mosaic dates from the third quarter of the 13th century. Also in Istanbul are a number of extraordinary mosaics in the double narthex (outer and inner porches) of Kariye Mosque (also known as the Church of Christ the Savior in Choraâ) of the early 14th century. These depict the life of the Virgin Mary and of Christ in a series of magnificent panels in glowing colors. 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, cornucopias, 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, gray, 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 (1180-90); 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-colored 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 (1130-43) 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 (tesselae) and are usually set in 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 Saint 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 cult statuettes. Turquoise was the favorite material of the artisans; it was cut in small pieces, polished, and set with a vegetable resin onto surfaces of wood, bone, stone, gold, shell, and pottery. Examples of this type of mosaic may be seen in museums in Mexico City, Harvard University's Peabody Museum in Cambridge, Massachusetts, and the Museum of the American Indian in New York City. See Pre-Columbian Art and Architecture.

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"Mosaics," Microsoft® Encarta® Online Encyclopedia 2003
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