The site has a large steep bank just beyond the northern boundary of the fort, which descends to the River Sowe. The elevation from the top of the bank provides good views of the landscape to the north for two or three miles
History
Four periods of occupation of the fort during periods of unrest in Roman Britain have been identified by excavation. The fort was built around AD 60 to act as a supply depot and headquarters for an unknown legion during the final campaign againstBoudica. From AD 64 it was used, in the second phase, by a cohort which reduced the size of the fort, but from which the principia, praetorium, two granaries and six barrack blocks have been excavated. A number of buildings were demolished to construct a gyrus. Many horse fittings, possible stabling, an extensive metalworking area, granary and storage space suggests a cavalry unit was present at this time. This second phase lasted until AD 77/8. The third period of AD 77/78-79 included construction of a double ditch system, a twin-portalled gateway on the south and occupation outside the defences until the fort was decommissioned. After AD 260, perhaps during the rebel Gallic Empire, it was recommissioned as a temporary fort with ditches on a similar alignment but slightly larger than that of Period 2.
Gyrus
The north, south and west sides followed the usual pattern for a Roman camp of straight ditches and ramparts. However, on the eastern side the defences bulge out around a circular structure with a diameter of. The sand and gravel subsoil had been dug out to a depth of and the area surrounded with a timber stockade. This ring, the only known "gyrus" in the Roman Empire, may have been used for training horses. The gyrus was added to the fort during its second period of occupation and its construction caused significant disruption to the fort. Having the gyrus within the fort affects not just the wall which curves to accommodate the structure deviating from the Roman playing card shape pattern but also the layout of the fort which is significantly different from the standard layout. This makes the fort unique not just in Britain but also in the Roman Empire.
Archaeology and preservation
The site was identified when large quantities of Roman pottery were found in the 1930s. In the 1960s, Brian Hobley, keeper of field archaeology at the Coventry Museum, commenced a long-term project to combine excavation with a study of the methods by which Roman camps were built. Archaeological excavations identified three distinct periods of occupation of the Roman military site. During the 1970s some features of the fort were reconstructed upon the original foundations: these are a section of the wall, a gateway modelled on images of Trajan's column, one of the three granaries and the gyrus. In 2001 a team of Canadian students unearthed a fragment of Roman Samian pottery and a Nero's head coin dating from 65 AD. Other finds have included a ring etched with a palm leaf. This type of design symbolized victory and was worn by successful gladiators. Evidence of Saxon settlement was unearthed in 2001 and finds evidencing mediaeval occupation include large post holes and a post-Roman ditch filled with pottery fragments. The fort is open for public, school visits and organised tours and has hosted many holiday excavation trips.