This is a highly accessible and closely reasoned attempt to extract the maximum historical information from Gildas' "On the Ruin of Britain" (De Excidio Britanniae), his jeremiad against the kings of fifth century sub-Roman western Britain. By taking into account the full text of what was intended to be a religious sermon rather than an historical account, Nicholas Higham is able to construct a highly plausible interpretation of Gildas' world: that he was writing c. 480 somewhere in central southern England south of the Thames, at a time when most of Roman Britain, though still retaining its Roman cultural identity, was already subject to Saxon overlordship; that the kings, who might have led a just war against the Saxons but whose immorality Gildas is at pains to vilify, were located in Cornwall and Wales, lands which were destined to remain outside Saxon control; that his call for moral reform to regain God's support was to fight this final war, in breach of the peace treaty that had stood for forty years or so, to drive the Saxons from Britain.
Higham ends his book with a short chapter dismissing the historicity of a King Arthur, whose necessity for existence is nullified by the author's thesis. Yet to my mind this begs the question (which he does not address) whether Arthur could have been the very righteous leader Gildas was hoping for, to fight the Saxons successfully with God's favour in the final conflict that Gildas sees as imminent. The legends record the tragedy of Arthur's ultimate failure and the final collapse of sub-Roman Britain. Yet these events would have taken place after the writing of "On the Ruin of Britain" and may even have been inspired by its call to arms. Nevertheless, this apart, I found the author's reasoned thesis very believable. For me it shed an inspiring light on what is traditionally a dark period in British history.