The place called Corinium by the Romans, and many variants of ‘Cirencester’ – ‘armed camp by the River Churn’ – after they left, replaced a nearby Celtic tribal capital, Bagendon, in the second and third centuries of the Christian era. The change of location was determined by the crossing of three Roman roads, Akeman and Ermin Streets, and the Fosseway. Like many old English towns, Cirencester owes its existence to Roman landscape engineering and a pax romana that imposed and protected movements of people, ideas and commodities throughout Magna Britannia. Later empires capable of restoring the roads and protecting the traffic depended on places like it to fill all the needs of the inter-regional traffic that converged on the space it occupied.

In the sense that it always belonged to an ‘imperial’ system, Cirencester was, and is, an imperial ‘city’. Henceforth it owed its existence, not to the location of a lordship, a castle or a monastic foundation, but to the ability of its inhabitants, generation after generation, to maintain numerous functions within changing, larger, social systems. Its prosperity and happiness depended on the ability of its inhabitants to connect the town's wealthy rural hinterlands with the larger, national and international networks to which its strategic crossroads led. This inescapable fact was at the heart of the struggles of the commonalty of Cirencester against a succession of lords imposed on the town by succeeding states.