OSMap: LR141, B25.
Type: Fort, Fort, Settlement, Bath House
|Ermine Street: SE (11) to Dvrobrivae Catvvellorvm (Water Newton, Cambridgeshire)
Ermine Street: N (17) to Saltersford (Lincolnshire)
Trackway: NW (8) to Thistleton
The Romano-British settlement at Great Casterton developed in the protective lee of a Roman auxiliary fort which was built on the north bank on the River Gwash during the early Claudian campaigns of the propraetor Aulus Plautius c.44AD. The defences of the fort, which lay to the north-east of the settlement, enclosed an area of around 6 acres (2.4Ha). The fort is large enough to comfortably house an auxiliary cavalry ala, or perhaps a cohors milliaria equitata, a mixed unit of cavalry and infantry a nominal one-thousand strong. Whatever the actual garrison, military occupation is thought to have ceased sometime around 80, presumably due to the unit being withdrawn for use in the campaigns of the propraetor Gnaeus Julius Agricola.
The first vicus-like settlement developed along the line of Ermine Street in a loop of the River Gwash, its beginnings were contemporary with the fort, and it continued to be occupied into the fourth century. Evidence of ore-smelting has been found within the defences and dated to the late-first century. A possible late-first century bath-house has been identified lying about 30 feet (c.10m) east of Ermine Street and 130ft (c.40m) from the later southern gateway of the town. A pottery kiln dated around 150-180AD was found (c.35m) east of Ermine Street close to the north-eastern defences of the town but predating them. Another undated kiln was found nearby.
The towns defences were arranged in the form of an elongated polygon of 7 or 8 faces which enclosed an area of 18 acres (7.3Ha) and were probably erected around the turn of the third century. They consisted of a 8ft (2.43m) wide stone wall, backed by an earthen rampart 30ft (9.14m) wide, fronted originally by a 7ft (2.13m) wide berm and three ditches, but later replaced in the early fourth century by a single ditch measuring an average 62ft (18.9m) wide and 11ft (3.35m) deep, cut 27ft (8.23m) out from the existing wall.
The Roman cemetery lay to the south of the settlement along Ermine Street, and continued in use during Saxon times.