The Colours
of Empire

A mosaic was not simply glued onto soil. Craftsmen prepared foundations of rubble, gravel and mortar, then placed cut tesserae into a bedding layer. A successful pavement depended on the stability and drainage of this construction just as much as on the hardness of its individual stones. Well-made floors could endure sustained use, but movement in the substrate, moisture, thermal stresses and abrasive dirt could weaken them.

Mosaics were installed in buildings with underfloor heating as well as in unheated spaces. A heated room required the engineering of the entire floor and hypocaust together. In the absence of a written maintenance register, there is no defensible single figure for a mosaic’s working lifespan. Some floors remained in use for decades; others were covered or altered when a room was remodelled, whether or not the earlier surface had worn out.

Chedworth supplies an unusually instructive sequence. The National Trust records a west-range corridor mosaic more than 30 metres long and a very large reception-hall mosaic uncovered during later excavations. The presence of multiple floors and building phases reveals successive investments, but not a simple story of each preceding mosaic wearing out. A change of plan, status or fashion could prove as important as damage.

Scientific provenance work provides the strongest evidence for organised supply. In Leicester, Tasker and colleagues examined microfossils in chalk tesserae from a fourth-century town-house. Their results showed that the chalk was not local; Baldock in Hertfordshire and Bridlington in Yorkshire were evaluated as the most likely source areas. The study used the Roman road network to assess possible connections, but did not recover the exact itinerary travelled by any shipment.

At Silchester, Wilkinson and colleagues likewise used microfossils in chalk tesserae to assess source formations. Some material was linked to plausible distant southern English sources rather than chalk immediately around the town. These studies overturn the assumption that common white tesserae necessarily originated nearby.

For Chedworth, specialist stone study has suggested sources near the villa and farther along the Coln valley, while material for particular purposes came from the Forest of Dean and Kimmeridge in Dorset. These are broad patterns of supply, not a proven route map with documented depots, carts and loading points. Water carriage might have mattered wherever accessible, but the route for a given floor remains an archaeological question.

The concentrations and artistic relationships of Romano-British mosaics around Corinium have encouraged discussion of a regional school or group of workshops. The term “school” describes stylistic and technical kinship; it does not prove the existence of an academy with a fixed address. Travelling craftsmen, workshops and copied design patterns can explain recurrent motifs.

Production involved several kinds of labour. Stone had to be won or collected, broken down, selected for colour, cut into pieces and carried to the site; preparatory workers established a level base; specialist setters resolved the pattern and fitted each tessera. Finely shaded figures demanded more design judgement and often smaller pieces than broad geometric fields.

We should not romanticise this as the solitary achievement of a master artist. Labourers, carriers, stonecutters, mortar workers, assistants and highly skilled designers participated in a chain of work. The visible mosaic is the final surface of an otherwise largely invisible economic system.

Demonstrated: mosaics in Britain used a variety of geological and ceramic materials; particular chalk tesserae at Leicester and Silchester were investigated through microfossil evidence; Chedworth contained both substantial mosaic floors and imported architectural marbles; and the written edict lists differentiated building-trade wage ceilings.

Probable or context-dependent: a considerable share of ordinary British mosaic material came through regional networks; Chedworth’s building campaigns reflected decisions about function and display as well as physical condition; craftspeople sometimes reused ceramic or roofing materials.

Not demonstrated for every floor: the quarry of each coloured tessera, an exact stone transport route, an ancient invoice, or a reliable universal lifespan. The claim that a particular imported stone colour was recognised by visitors as a deliberate status symbol remains plausible but requires site-specific evidence.