Using the author's wide-ranging background in the period's religions, culture, and chronology and both summarizing and synthesizing the advances in post-Roman studies since Leslie Alcock's 1971 classic Arthur's Britain, he has weaved historical documents, legends, archeology, and literature into a coherent and understandable history that begins with the weakening of Roman Britain and chronicles the transition of its people into sub-Roman communities and into British and Germanic kingdoms. Parallel to the political changes the book also describes the roles of religion, disease, the military, and the Irish and the Picts during the fourth, fifth, sixth, and seventh centuries.