The Middle Ages inherited from Antiquity a tradition of prophesy which, during those centuries took on fresh and exuberant vitality. This tradition foretold a millennium - in which the world would be inhabited by people at once perfectly good and perfectly happy. Humanity would enjoy a new paradise on earth, free of suffering and sin. Generation after generation was seized, at least intermittently, by a tense expectation of some sudden, miraculous event in which the world would be utterly transformed. Often these expectations become emmeshed with social unrest - with the desire of the poor to improve their material conditions. And when that happened movements were apt to arise which not only send tremors through the massive structure of medieval society but which also bear a startling resemblance to the great totalitaian movements of today. Drawing on a variety of contemporary resources, this book tells the story of those millennarian fanaticism of the Middle Ages and points to their persistence in the modern world.