Against Gravity

Lynne Lancaster

Lightweight Terracotta Vaulting Elements: Tracing Technology Transfer in the Western Mediterranean, 3rd c. BCE-1st c. CE
The imperial capital of Rome had some of the most advanced and innovative vaulted architecture from the ancient world, but even before the beginning of the empire, builders were experimenting with vaulting by creating new ways of using terracotta vaulting elements, usually in the context of bath buildings. In this paper I examine the origins of two of them: vaulting tubes and armchair voussoirs. The initial uses of both techniques developed in response to the need (and desire) for creating easy to build and lightweight vaults over the hot rooms of bath buildings at a time before the technology of concrete vaulting of central Italy had developed. The roots of the vaulting tubes can be traced back to a third-century BCE Greek bath at Morgantina and the armchair voussoirs to a third-century BCE Roman bath at Fregellae. Taking these two techniques, I trace their subsequent morphological development and geographical dissemination, and I suggest that the differing trajectories for each can be understood in relation to the expansion of agricultural production and pottery manufacture that occurred during the late Republic and early Empire in the western Mediterranean.