Earthen Empire: Earth and turf building in the Roman North-West

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Mud in Roman Architecture

Mud is not a material usually associated with Roman architecture. However, soil and turf (collectively ‘earthen’ materials) were widely used in unit-based (mudbrick and turf) and mass walls (rammed earth and cob) throughout the pre-Roman and Roman Mediterranean. These were cheap, easily available, and versatile materials, which over time were also adopted across the north-western provinces. Here they became a mainstay of military construction, as most dramatically demonstrated by the Antonine Wall in Scotland, possibly Rome’s largest earthen structure.

Despite their ubiquity, earthen building materials have been somewhat neglected in studies of Roman architecture, which have concentrated on a narrow range of structures and materials regarded as typically ‘Roman’ - brick, concrete, and marble most notably. Earthen materials were minimally processed, locally sourced, and often hard to identify archaeologically; the structures built in them are often also reflective of everyday pre-Roman construction practices and traditions.

The scholarly neglect of Roman earthen materials contrasts sharply with the recent revival of earth in modern architecture. Environmentally friendly and sustainable, architects and engineers take these materials seriously once more, even if the potential of turf remains largely underexplored. The field of engineering, in particular, now consciously engages with historic examples of earthen construction, which provide a crucial dataset, otherwise unavailable, for re-examining the long-term performance of these materials. Roman material remains entirely untapped from this perspective.

New light on old buildings

This interdisciplinary project, funded by the Leverhulme Trust (RPG-2018-223), was designed to shed new light on the use and properties of earthen buildings in the Roman North. Drawing together the expertise of archaeologists, architects, engineers and soil scientists, it focused on a series of case study sites, military and non-military. These included the Antonine Wall, Vindolanda, High Rochester, Carlisle, London, Richborough, and Valkenburg in the Netherlands. At each of these sites macro-scale analysis of the extant earthen architecture, including new excavation of it, was combined with microscopic analysis. These resulting datasets allow us to write a more complex, less selective, history of architecture in the Roman North, one that listens to vernacular voices while contributing to debates about how sustainable building today can responsibly use soil-based materials. 

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The Project Team

The Earthen Empire project was a collaboration between the School of History, Classics and Archaeology and the School of Engineering at the University of Edinburgh. The Principal Investigator was Professor Ben Russell (Classics), the Co-Investigator Dr Chris Beckett (Engineering). Dr Tanja Romankiewicz (Archaeology) was a Research Associate on the project between 2018 and 2021, and has continued to collaborate with the project team since 2021. Dr Riley Snyder (Engineering) was a Research Associate on the project between 2018 and 2022. Dr Rose Ferraby was a Research Associate in 2021. Benedicta Yi Xin Lin (Engineering) is the PhD student on the project, working on the mechanics of turf.

We have collaborated with a range of colleagues at various organisations and sites. Dr Tom Gardner (Historic Environment Scotland) performed all of the micromorphology on the project, using thin sections prepared by Dr Sabrina Save (TerraScope). We worked closely with Daniël Postma (Archaeo Build) on the practicalities of turf construction. We are grateful to our various collaborators: Dr Andy Birley at the Vindolanda Trust, Dr Geoff Bailey at the Falkirk Local History Society, Dr Tony Wilmott at Historic England, Dr Louise Fowler at MOLA, Dr Richard Carlton at The Archaeological Practice Ltd,  Dr Wouter Vos at Vos Archeo, and Drs Frank Gieco and Matthew Hobson at Wardell Armstrong.