Britain was never as thoroughly conquered as traditional historians would have us believe, according to Michael E. Jones. Among the provinces long occupied by Rome, Britain retained the slightest imprint of the invading civilization. To explain why this was true, Jones offers a lucid and thorough analysis of the economic, social, military, and environmental problems that contributed to the failure of the Romans.

Drawing on literary sources and on recent archaeological evidence, Jones disputes the theory that the Anglo-Saxon invasions were the determining agent in the failure of Romanitas. He argues instead that the success of the new warriors was a symptom of the inherent weakness of Romano-British society. Problems late in the era may have been worsened significantly by changes in the natural environment, such as climatic deterioration associated with harvest failure, famine, and changes in migration patterns.