Michael Frassetto's account of five centuries of social and spiritual turmoil is a vivid and telling mix of events, personality and ideas. His cast of characters includes Bogomil, an obscure priest of the Balkan countryside who introduced 'Manichaean' ideas to his parishioners; Henry the monk, the first true heresiarch, who eluded his captors and prepared Languedoc for the Cathars; Valdes the rich merchant who renounced worldly goods to found the movement that would evolve into the Waldensian Church; Pierre Autier, last of the Cathar 'perfects'; and John Wyclif the gentle Oxford scholar who with his disciple the Czech priest Jan Hus - the first disinterred from his grave in an English country churchyard, the other burnt as an urban spectacle - heralded the Reformation. This is history replete with passion, terror and hope, a key to the heart of medieval Europe.