Rounds (Archaeology)

Rounds (known in the Cornish language as ker or caer, plural kerow, and in western Pembrokeshire as raths) are a prolific regional class of small, univallate circular, oval, or sub-rectangular banked-and-ditched farmstead enclosures constructed across Cornwall and western Devon (the territory of the Iron Age and Romano-British civitas of the Dumnonii) between the Middle/Late Iron Age (c. 350 BCE) and the Early Post-Roman / Sub-Roman period (c. 600 CE). Enclosing an internal domestic courtyard typically measuring 35 to 90 meters across (0.1 to 0.8 hectares, averaging ~0.35 hectares) surrounded by a single stone-faced earthen rampart and external rock-cut ditch, rounds served as the standard enclosed rural settlement unit of Roman-period Cornwall—where continental-style masonry Roman villas were virtually absent (with the single exception of Magor Farm near Illogan). Through aerial cropmark surveys, geophysical magnetometry, and open-area excavations—most famously at Trethurgy Round near St Austell by Henrietta Quinnell—more than 1,000 rounds have been documented across the Cornish peninsula, illuminating over eight centuries of Dumnonian domestic architecture, tin-streaming trade, and agrarian continuity.

In southwestern British settlement archaeology, a Cornish round is distinguished from monumental multivallate summit hillforts (such as Castle-an-Dinas or Chûn Castle), coastal promontory forts ("cliff castles" such as Trevelgue Head and The Rumps), and large multiple-enclosure hillslope enclosures by its compact domestic scale and standardized univallate engineering:

1. Univallate Rampart and Ditch Circuit: A round is bounded by a single circuit of defense (univallate) comprising an external V- or U-profiled ditch cut 1.5 to 2.8 meters deep into the weathered granite (growan) or Devonian slate bedrock (shillet), backed by an internal earthen and rubble bank originally standing 2.0 to 3.5 meters high and 3.0 to 5.0 meters wide. At intact stone-rich sites such as Trethurgy and Castle Gotha, both the outer and inner faces of the earthen rampart were revetted with vertical drystone granite walling topped by a timber breastwork or hedge.
2. Plan Shape (Circular to Sub-Rectangular): While the English dialect term "round" (adopted in 18th- and 19th-century Ordnance Survey mapping) reflects the circular or oval geometry of examples such as Castle Gotha and Threemilestone, aerial photography shows that roughly 30% to 40% of rounds are sub-rectangular, D-shaped, or polygonal in plan ("rectilinear rounds" such as Grambla at Wendron and Trevisker).
3. Monumental Paved Gateway and Souterrain (Fogou) Integration: Access into the round was controlled by a single, heavily engineered gateway (usually facing east, southeast, or south downslope), paved with granite flagstones and flanked by heavy timber gateposts or stone orthostats. At several West Penwith and Meneage rounds—including Halligye, Boleigh, Pendeen, and Treveneague—an underground drystone-walled and lintel-roofed subterranean gallery called a fogou (the Cornish regional form of an Iron Age souterrain) was constructed either beneath the interior courtyard or opening directly into the enclosure ditch for cold food storage, ritual refuge, and ceremonial display.

The definitive archaeological reference site for the monument class is Trethurgy Round near St Austell, which was 100% excavated ahead of china-clay waste tipping by Henrietta Quinnell in 1972–1973. Because the entire internal courtyard and rampart circuit were stripped through nine stratigraphic phases spanning c. 150 CE to 500–550 CE (calibrated via radiocarbon dating and imported ceramic stratigraphy), Trethurgy revealed the internal organization of a Romano-Cornish enclosed hamlet:

1. Transition from Circular Roundhouses to Cornish Oval Houses: During the Middle and Late Iron Age (~350 BCE–70 CE, as at Trevisker and Threemilestone), buildings inside rounds were circular timber-post roundhouses. By the 2nd century CE, Cornish builders developed the Cornish Romano-British Oval House. At Trethurgy and Grambla, three to five oval granite-walled houses (9 to 13 meters long by 6 to 9 meters wide) stood around the inner perimeter of the stone-revetted rampart, leaving a paved central cobblestone courtyard open for work tasks.
2. Specialized Non-Domestic Buildings: Alongside residential oval houses (with clay-lined hearths and stone door pivot-stones), Trethurgy contained a four-post granary, a paved byre with a drainage sump for stalling cattle, and a circular stone structure (Structure Z) functioning as a household shrine.
3. Demographic Scale: Based on three to five contemporary houses at Trethurgy, Penhale Round, and Reawla, each round housed a multi-household farming community of 20 to 35 inhabitants—comparable in status to proprietors of banjo enclosures or proto-villas in south-central England.

Although Cornwall lay on the western periphery of Britannia with few paved Roman roads west of Exeter (Isca Dumnoniorum), artifacts and archaeobotany from excavated rounds demonstrate a mixed economy connected to maritime trade:

• Gabbroic Ceramics and Rotary Querns: Over 85% to 95% of pottery used inside Cornish rounds across a 700-year span—from Iron Age South-Western Decorated Ware and Cordoned Ware to Romano-Cornish flanged bowls—was potted from thermal-shock-resistant gabbroic clay of the Lizard Peninsula, accompanied by carved greisen stone bowls and rotary granite querns.
• Alluvial Tin Streaming (Cassiterite, SnO₂) and Pewter Demand: When Iberian tin mines declined in the 3rd century CE and demand for Cornish tin surged to manufacture Romano-British pewter tableware, rounds near granite valleys participated in alluvial tin streaming and smelting. Excavations at Trethurgy recovered a 7.5-kilogram plano-convex tin ingot, while Castle Gotha, St Mawgan-in-Pydar, and Reawla yielded stone moulds for casting tin, pewter, and bronze brooches.
• Post-Roman Eastern Mediterranean Amphorae (5th–6th Centuries CE): Several Cornish rounds—including Trethurgy and Grambla, alongside Tintagel—remained occupied after 410 CE; their latest phases (c. 475–550 CE) contain Late Roman 1 (Bii) and Late Roman 2 (Bi) amphorae and Phocaean Red Slipware bowls carried by Byzantine ships from the Aegean to exchange for Cornish tin.

Around the late 6th and early 7th centuries CE, Cornish rounds were abandoned as residential enclosures, though their banks lent the Cornish prefix Ker- or Car- to hundreds of modern farm names (Carloggas, Cargoll, Kerris). As documented by Sam Turner, Peter Herring, and Henrietta Quinnell, communities moved out of banked ker enclosures into unenclosed cooperative farming hamlets prefixed in Cornish with Tre- ("farming estate," such as Trethurgy, 300 meters from the abandoned round), accompanied by circular banked churchyards (lanns).

1. Quinnell, H. (2004). Trethurgy: Excavations at Trethurgy Round, St Austell: Community and Status in Roman and Post-Roman Cornwall. Cornwall County Council. https://doi.org/10.1017/S0003598X00094217
2. Nowakowski, J. A., & Quinnell, H. (2011). Trevelgue Head, Cornwall: The Importance of C. K. Croft Andrew's 1939 Excavations for Prehistoric and Roman Cornwall. Cornwall Council. https://doi.org/10.1017/S0079497X00001808
3. ApSimon, A. M., & Greenfield, E. (1972). "The excavation of Bronze Age and Iron Age settlements at Trevisker, St Eval, Cornwall." Proceedings of the Prehistoric Society, 38, 302–381. https://doi.org/10.1017/S0079497X00012160
4. Turner, S. (2006). Making a Christian Landscape: The Countryside of Early-Medieval Cornwall, Devon and Wessex. University of Exeter Press. https://doi.org/10.1017/S0003598X0009582X