Tesserae

Or a Certain Fragmentation of Thought and Image

I tend to pick up things.

Mostly fragments and broken bits – shells, pebbles, fragments of brick or ceramic. I have quite a collection now, though I suppose it cannot properly be called a collection, as it obeys none of the rules a collection should. I have a chip from Persepolis, a pebble from Delphi, a sand dollar from Uclulet, sandstone from Strasbourg cathedral and many other fragments. No labels; I cannot create proper collections; my mind does not work that way – a reluctance to collate, to compare, to catalogue and cross-index. I pick up old books, open them at random, in search of a thought or a phrase, a line of poetry or an epigram, that might be worth keeping in my haphazard collectanea. I pick up people’s faces in the street, sidelong passer-by glances, random appreciations of the line of a jaw or the corner of an eyebrow, filed away for future reference.

The other day, I picked up a word.

Tesserae.

It was had a crackled glaze with a few trapped bubbles, somewhat scuffed and scratched, as if by many feet or hands, and was light, rough and dusty on the back, with traces of mortar. Where could that have come from, I thought.

It seemed suddenly one of those word a hiereus could utter; nothing demotic about the sound, it seems to belong more to katharevousa than street signs… or a polyphonic juxtaposition of Tess and Dies Irae (d’Urbervilles and Days of Wrath), or… but time to stop fantasizing, I thought, and try to build a whole to fit the fragment. Exploring words is like buying a jigsaw puzzle in a jumble sale – no box, no image, just a plastic bag of pieces…

Tessera (plural tesserae) comes from the Greek word meaning “four-sided”.

The diminutive of tessera is, interestingly enough, tessella, which has mathematical implications well beyond me and best left alone, along with its cousin tesseract and other curvilinear parallelograms or four-dimensional geometrics.

Tesserae were also, for the Romans, small tablets of bone, wood, clay or ivory, used as tickets for events in amphitheatre. A number stamped on the tessera would direct the spectator to the appropriate section. Six-sided dice were also called tesserae. (“Tesserarian Art”, which sounds enticingly inscrutable and esoteric, simply refers to the practice of gambling.) The tessera is also known as an abaculus (diminutive of abacus) or abaciscus.

But, prosaically, it is mostly about mosaic. Mosaic, of course has nothing to do with Moses (Mosaic Law is not a guidebook to tiling floors) but with the Muses. Pliny the Elder tells us tessellated floors were first used in grottos dedicated to them. (He also mentions that the Muses are nine in number.) Pliny was also the first we know of to very helpfully explain how an ideal mosaic should be laid, in volume 36 of his Natural History, written around 77 A.D. (Only a couple of years before he found himself in the wrong place – Pompeii – at a most unfortunate time).

The precursor to mosaic as we know it is over 5000 years old. Clay cones about ten centimeters long were embedded in mud walls, their coloured heads forming repeating zigzag or lozenge patterns in red, black and tan. Cone mosaics in the Sumerian temples of Uruk date from c.3500–3000 BC.

Different materials were first used during the 2nd millennium BC, when chips of stone, shells and ivory enlarged the palette of colours and textures. Glazed tiles first came into use around 1500 BC, but it was the Roman Empire’s taste for tesserae that spread the technique throughout the then-known world. (In the rest of the world, wherever cities were being built, mosaic was being laid, or affixed to objects: pebble mosaics on footpaths in the far East, Aztec turquoise and shell masks and ornaments in Meso-America, 3rd-century mosaics in South Arabia, scantily-clad female musicians and dancers in the Roman mode gracing the floors of the palace of Sassanid king Shapur I in Bishapur in the mid 200’s.)

 

Left: Aztec mask with turquoise tesserae
Centre: Asarotos oikos.
Right: Asarotos oikos, 5th century, the Levant.
The whole of the Roman world is strewn with acres of mosaics. Snarling dogs captioned cave canem (apparently also a tongue-in-cheek warning not to inadvertently step on smaller dogs) grace entrances to villas. Gladiators poke blunt-looking spears at friendly-looking carnivores, bikini-clad female athletes pose with elegance, guests loll about at banquets; the full spectrum of Roman life in tiny marble and stone chips. Possibly, though, the most extraordinary theme is the asarotos oikos or Unswept Floor, first mentioned in Hellenistic times, work of Master Sosos of Pergamo. The original is lost, but Pliny (where would we be without Pliny?) makes a complete description of it*. It is basically what the name describes, a postprandial trompe l’oeil of a floor littered with scraps of food. Happily for me, I need not even go dig out the Naturalis Historiae. In the modest castle of Boudry, about three minutes’ drive south along the lake from Neuchâtel (Boudry is a sleepy village surrounded by vineyards with one claim to fame: Jean-Paul Marat, the revolutionary that Jacques-Louis David portrayed stabbed to death in his bath, was born there in 1743) is an extraordinary mosaic created around 450 AD in the Levant, combining a banquet and an asarotos oikos, complete with artichoke stems, chicken bones, shrimp heads, broken crabs and empty snail shells. If you read French, a full description is here.

The Roman Empire may have imploded, but the art of mosaic simply moved from villas and temples to the new basilicae that were springing up in the late 4th century as centralized secular power fragmented and reassembled under their lofty domes. The Christian East continued Roman traditions until the Arab conquest, and then continued on when Arab craftsmen adopted the same techniques. In Italy, cities like Ravenna became centers of the art, which flourished after the Byzantine conquest in the 6th century. Farther east, mosaic art continued in the Byzantine Empire for nearly another thousand years, until the fall of Constantinople in the 1453. Shimmering gold tesserae characterize the Byzantine mosaic. Made from glass with gold leaf applied, they echo the sumptuous richness of illuminated manuscripts but on a grandiose scale. The famous mosaics in the Hagia Sofia date from the 9th to the 11th centuries. The High Middle Ages witnessed another flowering of mosaic art in Rome, and Norman Sicily saw a blending of eastern and western influences. In the Levant, Synagogues were decorated with mosaics in the Roman tradition, the earliest surviving ones date from the 6th century and perhaps earlier. With the spread of Islam, mosques became showcases for mosaic; from North Africa to Persia, Spain became a crossroads paved in Moorish mosaic tiles. (Perhaps nowhere else in the world is there such a magical conjunction of East and West than in Cordoba or one of the most sublime places on Earth, the Alhambra.) But Byzantium reached northwards as well. Charlemagne is to thank for the renewal of mosaics north of the Alps, with the decoration of the Palatine Chapel in Aachen. (It did not catch on nearly as well as on the shores of the mediterranean – mosaics surround the Middle Sea in a veritable vermiculatum of tesserae.) There are early medieval mosaics scattered about Europe, but not in any great number. Farther east though, the Orthodox Church favoured mosaic over painting, with Byzantine artists working as far upriver as Kiev, in the wild lands of the Rus, or in the monasteries and churches of Greece. Mosaics eventually went out of style; frescoes were the favoured art of the late Middle Ages and the Renaissance, though Saint Peter’s Basilica features curious mosaics that resemble 16th-century paintings, in an intriguingly post-modern pixilated iteration of Baroque fashion and Byzantine tradition.

Despite a brief return to favour with Neo-Gothic and Art Nouveau, I suppose now most mosaics are in art galleries or swimming pools, but it’s one of the most ubiquitous and enduring (both in spirit and in situ) art forms the world has ever seen. Perhaps, though, because we spend much of our time treading on it while gawking at walls and ceilings, we don’t pay as much attention as we should. Who remembers the floor of the Sistine Chapel?

And of course, like any art form, it possesses a lexicon of extraordinary complexity. Here are a few styles of mosaic you might quite literally stumble on:

Opus lapili: Natural pebbles bound together in rough geometric patterns by packed earth or a mixture of sand and lime; the earliest mosaics, opus lapili were exclusively used for pavements throughout the Eastern Mediterranean. The term overlaps with Opus signinium, pebbles, small pieces of stone or terra cotta fragments, the most prevalent form of pavement in Roman villas from the 1st century BC to the 2nd century AD.

Opus tesselatum: the most common form of mosaic, consisting of small pieces or tesserae, usually cubes, made of stone, enamel, ceramic, glass or any other hard and durable material, placed tightly next to one another so that the underlying base is invisible. By far the most common form, they typify Hellenistic, Roman, early Christian and Byzantine mosaics. Evolving from pebble mosaics, it was widely in use by the beginning of the 2nd century BC. The tesserae form vertical or horizontal lines, not both.

Opus vermiculatum:  Frequently used in Hellenistic and Roman times, figural mosaic using tesserae which are cut to shape and size best suited for the design that was being created, to more closely follow figure contours and outlines. The word vermiculatum (“wormlike”) refers to the undulating rows of tesserae that follow the edge of figures or motifs. This technique was very similar to the Opus tesselatum, differing mostly in the way in which the pieces were cut to shape.

Opus musivum: Vermiculatum extends throughout the entire background.

Opus regulatum: All tesserae align both vertically and horizontally, as in a grid.

Opus classicum: When vermiculatum is combined with tessellatum or regulatum.
Opus segmentatum: A mix of small and large tesserae creating a geometric pattern.

Opus scutulam: Diamond-shaped tesserae arranged tightly.

Opus quadratum: Tesserae in the shape of a parallelepiped arranged in horizontal rows to achieve a checkered effect.

Opus reticulatum: Square tesserae arranged at an angle.

Opus spicatum: Tesserae (often pebbles) laid in a herringbone pattern.

Opus circumactum: Tesserae are laid in overlapping semicircles or fan shapes (a similar pattern is often found in paving stones).
Opus Alexandrinum: Decorative pavement typical of 9th century Byzantium. Small geometrically shaped pieces of coloured stone and glass paste that were arranged in geometric patterns dotted with larger disks of semiprecious stones.

Opus palladianum: Instead of forming rows, tesserae are irregularly shaped.

Opus incertum: Irregularly shaped small slabs of stone fitted together in a random fashion.

Opus Sectile: type of mosaic work in which figural patterns are composed larger tesserae cut to fit the various components of the design.

Pietra dura: Hard stone used in commesso mosaic work, using thin, cut-to-shape pieces of brightly coloured semiprecious stones, developed in Florence in the late 16th century. Pietra dura has much in common with marquetry and was reserved for furniture or smaller wall panels. Pietra dura was also known as parchin kari in Mughal India.
Micromosaic: using very small tesserae, in Byzantine icons and Italian panels for jewellery from the Renaissance on.

Alticado: Mosaic formed of polygonal glazed tiles, a blending of Gothic and Islamic styles typical of Moorish art.

Cosmati: Arrangements of small geometrically shaped tesserae alternate with large discs and strips, cosmati was popular in Rome in the 12th and 13th centuries.

 

Left: Mosaic of Christ Pantocrator, from the Deesis mosaic, Hagia Sophia
Centre: When mosaic imitates Baroque painting, from St Peters Basilica, Vatican.
Right: Occasionally nature outdoes itself: tessellated Pavement at Eaglehawk Neck, Tasmania.
Even the vague reading I’ve just done about the history and evolution of mosaic seems to take a person through the whole of European history, albeit underfoot, in a manner quite extraordinary for any art form, especially one we spend so much time treading on. Also quite troubling is that these are opera anonymii, as the artists and artisans left practically no names. So much art that is so personal and unique – all were working within the “confines” of style, but such an uncompromising medium calls for a high degree of improvisation and interpretation, especially when figurative – yet nameless, is equally unsettling. Trying to sum up all of the styles, influences and techniques in a few paragraphs is quite frustrating and the result is probably inaccurate and lacunary. (Seeing as I already wander about distractedly already, I wonder how wise this was. My poor wife, bless her, already has to patiently wait while I get lost in contemplation of walls and rooftops, now I’ll be shuffling my feet trying to puzzle out what I’m walking on. “Will you please hurry up?” “I’ll be right along. What do you think, reticulatum or quadratum?” “We’re late already.” “Coming. Scutulam, perhaps?”)

In the form of an afterthought, a connection fortuitous but tantalizing nevertheless, is Tartessos. Site of the earliest mosaics discovered in Europe, Tartessos dropped abruptly into obscurity in the 6th century BC, sinking into the mud at the mouth of the Guadalquivir, and leaving only a few tantalizing traces. Might Tartessos be the City of Tesserae, alluding to the mosaics? Most likely not even remotely true, but then there are pseudo-historians who offer it up as Atlantis or Tarshish. History is just full to the brim with fragments that never fit properly, or with mosaics held together by the mortar of wishful thinking.

Clearly, this doesn’t help me in organizing all the little broken bits of shell I gather, but only to remind me that inside every word there is a world. You just need to bend down and pick them up.
*Pavimenta originem apud Graecos habent elaborata arte picturae ratione, donec lithostrota expulere eam. celeberrimus fuit in hoc genere Sosus, qui Pergami stravit quem vocant asaroton oecon, quoniam purgamenta cenae in pavimentis quaeque everri solent velut relicta fecerat parvis e tessellis tinctisque in varios colores. mirabilis ibi columba bibens et aquam umbra capitis infuscans; apricantur aliae scabentes sese in canthari labro. —Pliny, Natural History, Book XXXVI.184
Special thanks to Ann Carling, who gathered up and supplied so many of the little pieces.