It then became a walled town in the Roman province of Britannia, at a major crossroads of the roads of southern Britain.

Given its access to east, west and northern domestic markets it was a centre of trade within Britain and with civilisations across the Channel and as far away as the Mediterranean.

Coins found stamped with "COMMIOS" show that Commius, king of the Atrebates, established his territory and mint here after moving from Gaul.

Imported Gallo-Belgic fine wares, amphorae and iron and copper-alloy brooches show that the settlement was high status.

Distinctive food was identified, including oyster shell, a large briquetage assemblage and sherds from various amphorae for olive oil, fish sauce and wine.

[9] Archaeobotanical studies have demonstrated the import and consumption of celery, coriander and olives in Insula IX before the Claudian Conquest.

There is a spring that emanates from inside the walls, near the original baths, and flows south-eastwards where it joins Silchester Brook.

[16] After the Roman withdrawal from Britain, Calleva Atrebatum remained inhabited, but its fortunes began to falter.

According to Daniel G. Russo the hypothesis that the city remained in use during the sixth century, thanks to its sturdy walls, is "attractive," but based largely on guesswork, as "there is no firm written or archaeological evidence that organised Romano-British urban life existed at Calleva beyond c. 450 at the latest.

)[19] A hypothesis has emerged that the Saxons deliberately avoided Calleva after it was abandoned, preferring to maintain their existing centres at Winchester and Dorchester.

[20] 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.

[21] The study of waterlogged macrofossils through a series of wells throughout the abandoned civilisation resulted in key evidence of animal stabling, hay meadows management, and the use of heath resources (such as heathers, gorse, and heathland grasses).

The most abundant crops that were found in the area are Capsella bursa pastoris, Chenopodium album, Polygonum aviculare, Stellaria media and Urtica urens, Fallopia convolvulus and Sisymbrium.

If ploughed the result is a "well-drained brown-earth soil" which, unirrigated, and without high fertilisation, yields low cereal returns.

[22] The study of plant remains from the across the city and especially Insula IX have shown that spelt, wheat and barley were the most common cereals consumed.

A wide range of fruits (apple, fig, grape), flavourings (celery, coriander, dill), and pulses (celtic bean, pea) were consumed.

The apse-ended basilica building has a layout comparable to early churches in the western Roman empire, but the date is likely to be pre-Constantinian.

[34] Built in two phases, the defence system of Calleva Atrebatum is evident in the remains of the North Gate.

Although it had long been known that there was an abandoned Roman civilisation, excavations ordered by the landowner, the Duke of Wellington, only began in the late nineteenth century.

Little further investigation occurred until the 1961 re-excavation of the early Christian Church where the researchers found that eighty to ninety percent of the excavation had been completed.

[44] Since the 1970s Michael Fulford and the University of Reading have undertaken several excavations on the town walls (1974–80),[45] amphitheatre (1979–85)[46] and the forum basilica (1977, 1980–86),[47] which have revealed remarkably good preservation of items from both the Iron Age and early Roman occupations.

[54] 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.