Calleva Atrebatum (Silchester) ("Calleva of the Atrebates") was originally an Iron Age settlement, capital of the Atrebates tribe, and subsequently a town in the Roman province of Britannia.  Its ruins lie to the west of, and partly beneath, the Church of St Mary the Virgin, Silchester, in the county of Hampshire. The church occupies a site just within the ancient walls of Calleva although the village of Silchester itself now lies about a mile (1.6 km) to the west.Unusually for a tribal capital in Britain, the Iron Age town was situated on the same site as the later Roman town although the layout was revised.

Iron Age
The Late Iron Age settlement at Silchester has been revealed by archaeology and coins of the British Q series link Silchester with the seat of power of the Atrebates. Coins found stamped with "COMMIOS" show that Commius, king of the Atrebates, established his territory and mint here after moving from Gaul. Small areas of Late Iron Age occupation have been uncovered and around the South Gate.  More detailed evidence for Late Iron Age occupation was excavated below the Forum-Basilica. Several roundhouses, wells and pits occupy a north-east - south-west alignment, dated to c. 25 BC - 15 BC. Subsequent occupation, dated to c. 15 BC - AD 40/50, consisted of metalled streets, rubbish pits and palisaded enclosures. Imported Gallo-Belgic finewares, amphorae and iron and copper-alloy brooches show that the settlement was "high status". Also distinctive evidence for food was identified, including oyster shell and sherds from amphorae which would have contained olive oil, fish sauce and wine. Archaeobotanical studies have demonstrated the import and consumption of celery, coriander and olive in Insula IX prior to the Claudian Conquest.

Roman
After the Roman conquest of Britain in 43 AD the settlement developed into the Roman town of Calleva Atrebatum. It was slightly larger, covering about 40 hectares (99 acres), and was laid out along a distinctive street grid pattern. The town contained a number of public buildings and flourished until the early Anglo-Saxon period.
Calleva was a major crossroads. The Devil's Highway connected it with the provincial capital Londinium (London). From Calleva, this road divided into routes to various other points west, including the road to Aquae Sulis (Bath); Ermin Way to Glevum (Gloucester); and the Port Way to Sorviodunum (Old Sarum near modern Salisbury).

The earthworks and, for much of the circumference, the ruined walls are still visible. The remains of the amphitheatre, added about AD 70-80 and situated outside the city walls, can also be clearly seen. The area inside the walls is now largely farmland with no visible distinguishing features, other than the enclosing earthworks and walls, with a tiny mediaeval church in one corner. There is a spring that emanates from inside the walls, in the vicinity of the original baths, and which flows south-eastwards where it joins Silchester Brook.

Silchester was finally abandoned in the 5th to 7th century, which is unusually late compared to other deserted Roman settlements. Most Roman towns in Britain continued to exist after the end of the Roman era, and consequently their remains underlay their more recent successors, which are often still major population centres. There is a suggestion that the Saxons deliberately avoided Calleva after it was abandoned, preferring to maintain their existing centres at Winchester and Dorchester. There was a gap of perhaps a century before the twin Saxon towns of Basing and Reading were founded on rivers either side of Calleva

Part of the city walls of Calleva Atrebatum

Silchester Eagle

Excavations at Calleva (Insula IX)

Silchester Amphitheatre Panorama 360 degrees.

Now primarily owned by Hampshire County Council and managed by English Heritage, the site of Calleva is open to the public during daylight hours, seven days a week and without charge. The full circumference of the walls is accessible, as is the amphitheatre. The interior is farmed and, with the exception of the church and a single track that bisects the interior, inaccessible. The Museum of Reading in Reading Town Hall has a gallery devoted to Calleva, displaying many archaeological finds from the various excavations.