The Middle Ages inherited from Antiquity a tradition of prophesy and gave it fresh and exuberant life. This tradition foretold a Millennium in which humanity would enjoy a new Paradise on earth, free of suffering and sin - a Kingdom of the Saints. Generation after generation was intermittently seized by a tense expectation of some sudden, miraculous event in which the world would be utterly transformed. Often these expectations became enmeshed with social unrest and movements arose which sent tremors through the massive structure of medieval society. Drawing on a huge variety of contemporary sources, this unique and compelling book tells the story of those Millenarian fanaticisms of the Middle Ages and points to their persistence in the modern world.