This book provides a new account of one of the most famous men of the English Middle Ages: Simon de Montfort. It is partly a study of the politics of Henry III's reign (1216-72), with which Montfort's career is closely interwoven; but it also looks at his lands, finances, following and religious ideals. Drawing on unusual sources, the author is able to make his biography as much a study of temperament and character as of a political career, and to write with a degree of psychological penetration rare in works on the medieval nobility.