The people of the former Roman province of Britain in the 5th and 6th Centuries had to make their living in difficult circumstances. Around them lay the ruins of imperial grandeur. In the cities, public buildings and private houses were in decay; on the frontiers, the forts were abandoned; in the country, the aristocratic villas were crumbling. This was not just a matter of physical decline or political change because as the Roman state was dismantled, so roads, bridges and ports were neglected, the coinage disappeared, government spending ceased and the elite of the armed forces and civil administration were no longer employing labor or consuming goods on a large scale. Trade dwindled and the former mass-producing industries collapsed. The native British population faced major upheavals in their way of life, including unemployment and a breakdown in law and order. The German immigrants from across the North Sea, who had been attracted by the opulence of the province, had to adapt to a changing society.
Without trade, easy communications or imperial government, the cities could not provide a living for a large population and almost everyone lived in the countryside. Here again they had no alternative but to adapt to a restricted economy. Apart from problems of security there would be no more large surpluses to be sold in the towns. The villas were taken over by succeeding generations of native British or Anglo-Saxon immigrants who put up buildings of wood. In some cases the territory around the villa persisted as an estate unit and the owners obtained tribute from the local peasants.
The priority of country-dwellers lay in providing for their own subsistence. In southern and eastern England they lived in timber houses often measuring 15 by 30 feet, associated with smaller structures with sunken floors built for storage, craft work (such as weaving) and accomodations for servants and dependants.
Even in the reduced circumstances of the post-Roman recession, households could not meet all of their consumption requirements from their own resources. They wove their own cloth and no doubt built their own houses and made implements from wood. But they needed iron weapons and farming tools and women wore ornate jewelry manufactured from copper alloy. These could only be supplied by specialists with crfating skills and raw materials so some surpluses from the land were exchanged.
A society with an emphasis on production for use and which had limited facilities for exchange was not likely to be deeply stratified. Elites collected foodstuffs from the peasants in some form but they had limited ways of disposing of goods once they satisfied their followers. While the people of 5th and 6th Century England adapted successfully to their post-imperial world, this was still a traumatic process. The losses of population far outweighed the gains from migration partly as a result of plague epidemics in the 6th Century, but more as uncertainties and the lack of economic opportunity discouraged marriage and child-rearing. We can only make an educated guess at the overall figures but the sparsity of settlements, the abandonment of towns and the retreat of cultivation could point to at least halving the population. Thus numbers fell from a peak of perhaps 5 million in the 2nd Century to less than 2 million by 600 AD.