Mosaic Tile: From Greek Pebble Floors and Roman Baths to Modern Pools

^{HOW PEBBLES, STONE CUBES, GLASS SMALTI AND GLAZED TILE BECAME THE SURFACE OF FLOORS, BATHS AND POOLS}

Mosaic tile work is built from tesserae, small pieces of stone, glass, ceramic or other hard material cut into cubes or other regular shapes, and before them from natural pebbles. The earliest mosaics were floors of natural pebbles, found in Asia Minor from the 8th and 7th centuries BC. By 200 BC Hellenistic workshops had replaced pebbles with cut cubes called tesserae, and Roman builders laid them through houses, villas and public baths, often in black and white with marine subjects. Glass and gold glass carried mosaic onto the walls and vaults of Ravenna, glazed cut tile produced the zellij of Morocco, and from 1927 to 1934 one-inch glass tiles covered the Roman Pool at Hearst Castle in California.

^{WHERE DID MOSAIC COME FROM? PEBBLE FLOORS FROM ASIA MINOR TO PELLA}

Pebble mosaic uses natural pebbles arranged into decorative or pictorial patterns, and it was used only for pavements. According to Britannica, it was the earliest type of mosaic in the eastern Mediterranean, first appearing in excavated floors in Asia Minor dating from the 8th and 7th centuries BC. The first examples had rough geometric designs. By the 5th century BC Greek artists were using pebbles to render delicate figures and detailed ornament, although most pebble floors relied on a contrast of dark and light stones rather than a full range of colour. At Olynthus in northern Greece, a series of black-and-white floors from about 400 BC shows mythological scenes.

The pebble floors of Pella in Macedonia date from the late 4th century BC. A few of them are multicoloured, and they show monumental figures of people and animals. The later floors at Pella also mark a change in technique: pebbles were combined with stone tesserae chosen for the intensity of their colour, and strips of lead or terracotta were set into the floor to outline details. Pebble mosaic remained the major form of mosaic decoration until about the 3rd century BC, when it began to be replaced by floors made of cut stone cubes.

^{WHAT ARE TESSERAE? OPUS TESSELLATUM AND OPUS VERMICULATUM}

A tessera is a small piece of stone, glass, ceramic or other hard material cut into a cube or another regular shape. By 200 BC tesserae had replaced natural pebbles in Hellenistic mosaics. The earliest were cut from marble and limestone, and stone remained the main material into Roman times. Glass tesserae, called smalto, appeared between the 3rd and 1st centuries BC, cut from slabs of glass. Because glass was fragile underfoot, floor mosaicists used it sparingly, mainly for the blues, reds and greens that natural stone could not easily supply.

Ancient mosaicists worked in two main techniques. Opus vermiculatum, a name meaning wormlike, used small, closely set tesserae in undulating rows that allowed fine gradations of colour and precise outlines. It was generally reserved for the emblema, a central figural panel, which was surrounded by geometric or floral designs in opus tessellatum, a technique of larger tesserae. The earliest known example of vermiculatum is an emblema of about 200 BC showing a personification of Alexandria, now in the Greco-Roman Museum in Alexandria. The Alexander Mosaic from Pompeii, showing the Battle of Issus between Alexander the Great and Darius III and now in the Museo Nazionale in Naples, probably copies a 4th-century BC Greek painting; Britannica describes the technique's aim as "to paint in stone".

In Italy, mosaics first appeared in the late 2nd century BC under Hellenistic Greek influence, with tiny irregular stone pieces that imitated the effects of painting. The Getty Museum dates the Alexander Mosaic, from the House of the Faun, and the Nile Mosaic from Palestrina to about 100 BC, both emblemata of this kind. By the late 1st century BC Italian floors ranged from colourful figural scenes to mainly black-and-white geometric and floral designs. Vermiculatum declined after the 1st century AD but remained the main technique for finer pictorial mosaics until the 4th century.

^{HOW WERE ROMAN MOSAIC FLOORS LAID?}

The Roman writer Vitruvius set out the preparation of a pavement in Book VII of his treatise on architecture. The ground was first examined to confirm it was solid throughout, then covered with a levelled layer of rubble and rammed if the earth was loose. On timber floors, fern or straw was laid down first so that the lime would not damage the wood. Over this went a layer of stones, each no smaller than would fill a man's hand. A bed of rubble and lime followed, mixed three parts to one for new rubble and five parts to two for old, and beaten with wooden beaters by a number of men until it was about three quarters of a foot thick.

The upper layer was three parts potsherds to one part lime, spread to a thickness of not less than six inches, and the pavement was laid on it to rule and level, whether of cut slabs or of tesserae. The surface was then rubbed down so that no edges stood proud and the joints were perfectly smooth, with the edges of the tesserae completely smoothed off. After rubbing and polishing, marble dust was strewn over the floor and a coat of lime and sand applied.

^{MOSAIC IN ROMAN BATHS: THE BLACK-AND-WHITE FLOORS OF OSTIA}

From the late 1st century AD black-and-white mosaics became common, especially in Rome and central Italy. Complex geometric patterns came to cover whole floors, as in the Getty Museum's Medusa mosaic. Black-and-white work may have been a cheaper alternative to polychrome tesserae, yet high-quality examples were laid at Hadrian's Villa at Tivoli and the Palazzo Imperiale at Ostia in the 2nd century AD. After the eruption of Vesuvius in AD 79, Ostia provides the richest evidence for the development of mosaic, with many of its floors dating to the 2nd and early 3rd centuries AD.

Most of the Ostia floors are black-and-white figural works, often with marine subjects, and the Baths of Neptune and the Baths of the Lighthouse are among the clearest examples. The mosaics of the Baths of Neptune date to the reign of Hadrian, AD 117 to 138. One room shows Amphitrite, Neptune's wife, riding a sea horse among tritons. A second shows Neptune with his trident driving a chariot drawn by four sea horses, surrounded by dolphins and tritons blowing on shells. The frigidarium, the cold room of the Roman bathing sequence, has Scylla, the monster who killed seafarers, surrounded by marine deities, subjects the park's panel links to the theme of water.

^{GLASS AND GOLD: HOW BYZANTINE MOSAIC MOVED ONTO WALLS AND VAULTS}

From the 1st to the 3rd centuries AD, wall mosaics made glass tesserae in every hue their major material, while stone was kept mostly for floors. Gold glass entered Roman mosaic in the 4th century AD: gold or silver leaf was sandwiched between layers of glass and the result cut into pieces. In Early Christian and Byzantine churches glass became the main material of wall and vault mosaics, and solid fields of gold tesserae formed the gold backgrounds found in almost every scheme. Opus vermiculatum was abandoned for walls and vaults in the Early Christian period.

Ravenna in north-east Italy became the capital of the Western Roman Empire in 402, then the Ostrogothic capital under Theodoric and his successors, and later a Byzantine capital in Italy. Eight of its monuments, all built in the 5th and 6th centuries, were inscribed by UNESCO in 1996 as the Early Christian Monuments of Ravenna, with the first criterion citing the supreme artistry of their mosaic art. The Mausoleum of Galla Placidia is decorated with mosaics on a dark blue background, the Neonian Baptistery has multicoloured mosaics in its cupola, and the Church of San Vitale, from the time of Justinian, combines western and eastern traditions.

^{WHAT IS ZELLIJ? CUT GLAZED TILE MOSAIC FROM FEZ}

Ceramic tesserae were used only occasionally in antiquity and the Middle Ages. In Morocco, glazed ceramic is the material of zellij, also written zilij, a technique of polychrome-glazed cut tilework. The Metropolitan Museum of Art in New York shows it in the Patti Cadby Birch Moroccan Court, which was built and decorated on site in 2011 by craftsmen from Fez working for the Naji family's company, Arabesque, Inc. The court's tile designs are based on the dado panels of the Alhambra Palace in Granada, and every element was made with traditional techniques and materials.

The walls follow the three-part arrangement traditional in Moroccan and Andalusian courtyards. The lower section carries brightly coloured geometric zellij, the middle section carved stucco, and the top carved cedar wood that projects from the walls to narrow the light shaft, finished with green roof tiles. The tile patterns start at the centre of each star and radiate outward in interlacing stars and pentagons, so that the design appears to continue beyond the edges of each panel. The court also holds a set of carved marble columns from Granada dated to about 1350 to 1400, given to the museum by The Hearst Foundation in 1956.

^{FROM VENICE AND THE VATICAN TO THE MOSAIC SWIMMING POOL}

The mosaics that completed St Mark's in Venice were made from cartoons by Titian, Tintoretto, Giuseppe Salviati and Paolo Veronese, and the Venetian workshops remain significant in the field. The workshops attached to St Peter's in Rome became centres of mosaic making, artists were summoned from them across Europe, and the Vatican's mosaic school is still active. In the 19th century, historicism and a move away from Neoclassicism's dismissal of Byzantine art raised both interest in mosaic and demand for it. In the 20th century, painters including Marc Chagall were drawn to the abstract qualities of medieval mosaic, Mexican muralists produced large public mosaics, and after the Second World War artists experimented with larger, less regularly cut pieces. Prefabrication by the indirect method, together with improved tessera manufacture, led to large-scale output for churches, town halls and opera houses. Ceramic tesserae, rare in antiquity, became a major material of modern mosaic.

The Roman Pool at Hearst Castle in California was built from 1927 to 1934. It appears styled after an ancient bath such as the Baths of Caracalla in Rome, of about 211 to 217, and its water was heated like a tepidarium. The pool is covered from ceiling to floor with one-inch square glass mosaic tiles, mainly blue or orange or clear with gold fused inside, and the vaulted arches are of blue and gold smalti. The muralist Camille Solon developed the tile designs, some of them drawn from the 5th-century Mausoleum of Galla Placidia in Ravenna, and the roofs and dome are covered with night-blue mosaic powdered with stars. Marble was used only in the statues, eight of them carved by Carlo Freter in Pietrasanta, Italy.

^{THE SPA AT MANDARIN ORIENTAL JUMEIRA, DUBAI}

The Spa at Mandarin Oriental Jumeira, Dubai was completed in 2019 to a DesertScape concept drawn from curved, ridged dunes. It has nine treatment rooms with full-height windows to the beach and the Gulf, plus a VIP suite and a hammam suite, and seating in cocoon linen pods. Its vitality room is built around a circular dark mosaic pool, enclosed by curved stratified marble walls whose grain runs continuously, under a rippled cove-lit ceiling. The pool is finished in mosaic.

Mosaic paved the Baths of Neptune at Ostia in the reign of Hadrian, AD 117 to 138, including a room of Neptune driving a chariot of sea horses and a frigidarium floor of Scylla among marine deities. It also covers the Roman Pool at Hearst Castle, built from 1927 to 1934 in the manner of an ancient Roman bath such as the Baths of Caracalla, from floor to ceiling in one-inch square glass tiles, mainly blue or orange or clear with fused gold.

SOURCES

1. Britannica Pebble mosaic
2. Britannica Tessera
3. Britannica Opus vermiculatum
4. J. Paul Getty Museum Roman Mosaics in the J. Paul Getty Museum: Italy
5. University of Chicago, LacusCurtius Vitruvius, On Architecture, Book VII
6. Parco archeologico di Ostia antica Terme di Nettuno: the mosaics
7. UNESCO World Heritage Centre Early Christian Monuments of Ravenna
8. The Metropolitan Museum of Art The Patti Cadby Birch Moroccan Court
9. Britannica Mosaic: Renaissance to modern mosaics
10. Hearst Castle The Pools