Like his crusading father before him, Simon de Montfort’s combination of charisma, determination and fearlessness, reinforced by a wife with similar qualities, made him one of the greatest men of his age. This biography follows his life from his birth and upbringing in France until his defeat and death at the hands of the future Edward I. The pivotal year was 1264, when Montfort captured Henry III in battle, established a constitutional monarchy and, in the act he is most famous for, revolutionised the representation of Parliament, the future Commons. While calling him the founder of that institution begs too much, Montfort recognised and cultivated a new awakening in national identity and political awareness not seen since before the Norman Conquest two centuries earlier. Henry’s long reign of fifty-six years saw many changes taking place in England and on the Continent, most strikingly the rise of humanism and power politics, and Montfort’s entree to the courts of Paris and Rome was instrumental in his rebellion against the king. Not for another four hundred years, until the advent of Oliver Cromwell, would England see a revolution led by a figure of comparable stature.