M is for Mosaic

First developed in antiquity, this decorative technique spread throughout the Christian and Eastern worlds over the centuries. Since the beginning of the 20th century, the technique has enjoyed a revival.

Almost every era has succumbed to the mosaic’s palette of materials and colors, and taken advantage of its great versatility. The range of elements used to form its primary components abound. More than the material itself, it is the small size and irregularity of the elements that make up a mosaic that best distinguishes this technique from other forms of cladding: pebbles, terracotta pieces or small elements called tesserae, cut or broken from slabs of limestone, marble or ceramic.These tesserae can also be cut from colored glass rods or mother-of-pearl pieces. Mosaics therefore lack the perfect regularity of cut stone pavements, like hardstone marquetry. These various elements are fixed with mortar or glue, following a preparatory design traced on the floor or walls, and form a solid, waterproof surface whose utilitarian character was appreciated in antiquity. The mosaicist then arranges the tesserae to imitate a more or less complex tapestry or mural. A monochrome or bichrome geometric mosaic is undoubtedly the simplest of creations, it’s far more difficult to form canevas, compositions assembling different scenes illustrated in fine mosaic, called emblemata. The complexity is overcome by creating these mosaics in the workshop, which are first fixed on a removable support­­­—travertine, terracotta, wood—then installed in the building, usually on the floor, sometimes on the wall, and linked together by opus tessellatum frames, using thicker tesserae. Capturing the possibilities offered by the variety of materials and the multitude of possible technical combinations characterizes the talent and tastes of different eras and cultures.

Multiple Techniques

Among the most common, opus tessellatum, with tesserae ranging from 4 to 20 millimeters on each side, is the most versatile type of tile and can be used for all kinds of designs. Opus vermiculatum tesserae are no larger than 4 mm on each side, while opus figlinum tesserae are arranged edgewise and vary in orientation to imitate the weave of a basket. As for opus signinum and musivum, the tesserae are scattered randomly on the floor in the case of the former, and on the walls of caves dedicated to the muses in the case of the latter; the latter has the particularity of mixing shells, glass and pumice with the tesserae. Attested since the third millennium BCE in Mesopotamia, mosaics entered their golden age during the Greek classical period (507-323 BCE). Initially, pebbles were used, playing with their colors in geometric or figurative, bichrome or polychrome motifs. The virtuoso mosaics of Olynth are the finest expression of this tradition. A privilege of the elite, mosaics maintained a close relationship with painting, a relationship that became even more pronounced with the development of tesserae in the Hellenistic period (323 BCE – 31 CE). While most mosaicists remain anonymous, Sôsos of Pergamon (c. 133 BCE) remains famous for his “poorly swept floor”, asarotos oikos, a polychrome mosaic scattering the remains of a meal in an admirable trompe-l’oeil effect. The work gives an idea of the finest Greek creations, sometimes portable in the form of ‘easel’ mosaics. This format would endure in Byzantine art, whose creations were much coveted during the Renaissance. The Hellenistic style continued into the early Roman Empire, but black-and-white mosaics gradually took over in Italy, as found in numerous Pompeian floors. While polychromy enjoyed a certain success in Gaul and held its own in North Africa, it was poised to change in scope. The rise of Christianity immersed sacred architecture in golden mosaics covering columns, walls and domes. In the upper parts, tesserae made of agglomerated glass, into the thickness of which gold or silver leaf has been inserted, are slightly inclined in the mortar, allowing light to play on their surface. Umayyad mosaics adopted the same technique, achieving a perfect mastery of glass and its coloring: those in the Cordoba mosque are a magnificent example. This art continued to flourish for some time in the Christian world, notably in the Norman kingdom of Sicily in the 12th century, before declining. It was revived in the 15th and 16th centuries, when Titian, Tintoretto, Salviati and Veronese signed cartoons for St. Mark’s Basilica in Venice. At the end of the 16th century, the Vatican’s new mosaic workshop decorated the domes of St. Peter’s Basilica. Its constant experimentation gave rise to almost thirty thousand shades of enamel—pastes of glass colored in the mass—and, in 1775, to tesserae measuring less than a millimeter. From then on, micromosaics adorned the precious souvenirs of the Grand Tour and the diplomatic gifts of the popes.

In Recent Years

In the 19th and 20th centuries, mosaics made a comeback in architecture with Eugène Grasset, Antonio Gaudí and Fernand Léger, but shone brightest in Mexico. Pre-Columbian mosaics of turquoise, jade and obsidian, glued with resin onto all kinds of supports, were already fascinating for their vibrant colors. A few centuries later, artists such as Diego Rivera and Juan O’Gorman would prove worthy heirs to this artistic past, creating monumental, typically Mexican mosaics. Let’s hope the 21st century doesn’t leave the tesserae in the dust.

Worth Seeing
Mosaics of antiquity at the Louvre, Fernand Léger’s mosaics at the church of Notre-Dame-de-Toute-Grâce in Passy (Haute-Savoie) and Odorico’s mosaics in Rennes (Ille-et-Vilaine).