For the third edition, this comprehensive history of the great heretical movements of the Middle Ages has been updated to take account of recent research in the field. First published in 1977, this comprehensive history of the great heretical movements of the Middle Ages provides a vivid account of the dark, often secret, world of dissent and protest against the medieval churches of Rome and Byzantium. Malcolm Lambert examines the origins and nature of these heresies, and looks at how medieval churchmen grappled with deviation, sometimes by preaching and argument, more often by armed force, imprisonment and the stake. - Publisher.