Roman Brick and Tile Stamps

Roman brick and tile makers often pressed a stamp into the wet clay before firing. These brick stamps (Italian bolli laterizi) are now one of the most useful tools for dating Roman buildings, including their roofs, because bricks and tiles came from the same yards and broken fragments of the two are often hard to tell apart.

Origins and content

Stamping began around the middle of the 1st century BC. Early stamps were made with a hardwood or metal die and usually gave only a person's name, sometimes with the name of the brickyard. As fired brick became the main building material of the early Empire, more producers entered the trade and stamps became more detailed. From AD 110 they began to include the names of the consuls of the year, which allows a stamped brick to be dated to a single year.

A full stamp could record:

• the owner of the estate (dominus);
• the supervisor of the yard (officinator);
• the brickyard itself;
• the consuls in office.

Production

Most brick and tile came from yards on large estates owned by wealthy families with access to good clay. The workforce had three tiers: owners, supervisors and the workers who made the bricks, usually slaves. Output was regulated, and over time the business became an imperial monopoly. A brickyard belonging to Domitia Calvilla, mother of Emperor Marcus Aurelius, has been found at Bomarzo, north of Rome.

Military stamps

Across the provinces, army units ran their own kilns, including mobile ones, and stamped tiles and bricks with the legion's mark. A 1993 excavation in Merseyside, England, recovered more than 300 kg (660 lb) of tile and kiln remains, including tiles stamped by Legio XX Valeria Victrix. Such finds show where the army was operating as well as when.

Roofs and the tile industry

The standard Roman roof combined flat tegulae with curved imbrices, and these were produced in enormous numbers alongside bricks. Stamps on roof tiles therefore date not only walls but also roofing phases and repairs. Broken tiles were also recycled by crushing them into mortar.

Use in archaeology

Once treated as curiosities, stamps are now carefully recorded. Combined with architectural evidence, they provide a reliable method of dating Roman construction and show changing patterns of demand for building materials.