For many in the Roman province of Britain, the cycle of subsistence farming and exchange of specialist goods (like salt or milling stones) with neighbours or more distant communities remained unchanged long after Roman conquest.
SUPPLYING THE ARMY
The only possible means of meeting the supply requirements of the immense army in Britain, however, was the development of a money economy, driven by military pay and long-distance trade.
Very little evidence of commerce survives in the archaeological record, except for pottery, which does not rot and could not be recycled. So for the most part, we have to imagine the foodstuffs, livestock, textiles and other perishable goods that would have formed the bulk of consignments.
HOME AND ABROAD
During the conquest period the army of the province of Britain sucked in samian ware and other fine pottery from Gaul, and made humbler coarsewares itself. Imports arrived via the province’s trading ports, such as London – which grew rapidly into one of the largest Roman cities north of the Alps.
By the AD 120s the army on Hadrian's Wall was using pottery produced by the industry of southern and midland Britain, as well as Gallic imports. British landowners and their workers, as well as economic migrants and merchants from overseas, had joined in the military supply chain and had developed ways of profiting from the army’s needs.
Britain’s cities also consumed Roman-style pottery and other goods, and were centres through which goods could be distributed elsewhere. At Wroxeter, Shropshire, the shop-stock smashed into a gutter during a 2nd-century fire reveals that Gaulish samian ware was being sold alongside mixing bowls from the Mancetter-Hartshill industry of the west midlands.
Gradually there was a shift away from imports from the Mediterranean and Gaul as the local economy grew and Britain became more self-sufficient. Army supply was more local than ever, with few imports from the Continent. A major pottery industry (Crambeck) was established in the north, close to Hadrian’s Wall, and there were large concentrations of potteries in the Nene Valley and Hampshire.
Whereas the army of the conquest had consumed vast quantities of olive oil, imported in amphorae from Spain, the 4th-century army subsisted almost entirely on local produce.
The growth of the economy of what was a peripheral frontier province was made strikingly clear by the growth of the so-called small towns, a network of settlements that did not have the same status or appearance as a city (or civitas capital).
These urban centres were like nothing in the pre-Roman Iron Age. They had sizeable populations performing well-developed industrial or commercial activities, most commonly ironworking, pottery and glass manufacture. They were places where agricultural products and services could be exchanged.
Some were more obviously agricultural in character: rural villages, essentially, of varying size. The small towns tended to be on the road networks (like Wall in Staffordshire), sometimes originating on the sites of former military bases.
In the developed province of the 3rd and 4th centuries, the distribution of small towns coincided with that of villas. In these towns, villa owners and small-scale farmers could obtain specialist products (like tools) and services (such as a local vet).
Lowland Britain in the 4th century was agriculturally prosperous enough to export grain to the Continent. This prosperity lay behind the blossoming of villa building and decoration that occurred between AD 300 and 350.