Roman brick

Roman brick can refer either to a type of brick used in Ancient Roman architecture and spread by the Romans to the lands they conquered; or to a modern type inspired by the ancient prototypes. In both cases, it characteristically has longer and flatter dimensions than those of standard modern bricks.

The Romans only developed fired clay bricks under the Empire, but had previously used "mud brick", dried only by the sun and therefore much weaker and only suitable for smaller buildings. Development began under Augustus, using techniques developed by the Greeks, who had been using fired bricks much longer, and the earliest dated building in Rome to make use of fired brick is the Theatre of Marcellus, completed in 13 BC.

Roman brick was almost invariably of a lesser height than modern brick, but was made in a variety of different shapes and sizes. Shapes included square, rectangular, triangular and round, and the largest bricks found have measured over three feet in length. Ancient Roman bricks had a general size of 1½ Roman feet by 1 Roman foot, but common variations up to 15 inches existed. Other brick sizes in Ancient Rome included 24" x 12" x 4", and 15" x 8" x 10". Ancient Roman bricks found in France measured 8" x 8" x 3". The Constantine Basilica in Trier is constructed from Roman bricks 15" square by 1½" thick. There is often little obvious difference (particularly when only fragments survive) between Roman bricks used for walls on the one hand, and tiles used for roofing or flooring on the other, and so archaeologists sometimes prefer to employ the generic term Ceramic Building Material (or CBM).

The Romans perfected brick-making during the first century of their empire and used it ubiquitously, in public and private construction alike. The Romans took their brickmaking skills everywhere they went, introducing the craft to the local populations. The Roman legions operated mobile kilns and introduced bricks to many parts of the empire. Roman bricks are often stamped with the mark of the legion that supervised their production. The use of bricks in southern and western Germany, for example, can be traced back to traditions already described by the Roman architect Vitruvius, although he probably refers to mud brick. In the British Isles, the introduction of Roman brick by the Ancient Romans was followed by a 600–700 year gap in major brick production.

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