This is a study of the religious ideas and motivation of the laymen who fought in the First Crusade (1095-1101). Marcus Bull argues that the laity's crusading zeal cannot be understood simply as a reflection of the preoccupations of educated ecclesiastics. His scholarly and sophisticated analysis shows that elements traditionally regarded as central to the crusade's origins--the Peace of God movement and the Spanish Reconquest--were in fact of minimal significance. Through a study of three regions in southwestern France, Bull uncovers the true dynamic of crusade enthusiasm: the beliefs and practices of pious laymen in intimate contact with local religious communities. He shows that the crusade was an expression of everyday, but genuine, piety.