Following the evacuation of the Roman troops after AD 410, Britain entered a period characterized by the co-existence of competing military systems. The Britons, who had been progressively ‘Romanized’ during the previous centuries, retained many elements of the military organization that was typical of the Late Empire; these, however, were mixed with important components drawn from pre-Roman Celtic tradition. In Wales the ‘Romanization’ of the local population had never been complete and the Britons from this region fought in a way that had evolved relatively little from the pre-Roman era. The military forces of Sub-Roman Britain faced two main kinds of enemies from the early fifth century AD, the Celtic peoples coming from Scotland or Ireland and the Germanic communities coming from Continental Europe, each bringing distinctive styles of warfare and equipment drawing on their own traditions. Gabriele Esposito details the military campaigns that took place in Britain from the mid-fifth century AD to the final phase of Saxon expansion. He describes how the Late Roman system of military defence crumbled in Britannia and how its remnants gave birth to the Sub-Roman armies of the so-called ‘Arthurian Age’. He considers the most recent theories regarding the historicity of the figure of Arthur, and provides full detail on the military history of the Britons’ enemies: Picts, Scots, Saxons, Angles and Jutes. The greatest attention is given to detailed descriptions of the organization, equipment and tactics of the various military forces, with numerous colour photographs showing replica weapons, armour and costume in use.