Diarmaid MacCulloch writes:
Fortunate is the reader seeking the story of early Christianity in Britain. At its heart is one of the greatest and most readable of medieval historians, the Venerable Bede, and its modern exponents include such engaging and stylish writers as Charles Thomas, Leslie Alcock and Henry Mayr-Harting. The literary sources have attracted much idiosyncratic talent, for they possess the fascination of a cryptic crossword in which one must sift fact from propaganda, post-Norman Conquest forgery from dimly glimpsed ancient original. At one pole, there is the sixth-century Welshman Gildas, whose gloomy rhetoric in De Excidio et Conquestu Britanniae testifies to the survival of solid classical education after the Roman legions departed. At the other pole, six centuries later, stand the heroic liar Geoffrey of Monmouth, whose Historia Regum Britanniae conjured up Arthurian splendour from scrappy British memories that they had had a champion against the Saxons, and some ingenious Welsh bishops who, furious at the unholy alliance of Anglo-Saxon and Norman Johnny-come-latelies, consolidated their prestige and estates against the interlopers by inventing evangelistic exploits for ancient saints like Dyfrig or David. Malcolm Lambert is a judicious guide to the shifting opinions of scholars amid these quicksands, casting a sceptical eye even on Bede’s motives for glorifying and sanitising the Roman mission to the Anglo-Saxons.