In 1258, England underwent a political revolution, the effects of which can be felt even now. On May Day a small band of earls converged on Westminster Hall. Armoured and carrying their swords, they demanded reform from King Henry III. The result was seven years of chaos and constitutional experiment. In 1264, after a battle at Lewes in Sussex, Henry himself was taken prisoner. A year later, the king’s son, the future Edward I, destroyed the rebels in a second great battle at Evesham. Meanwhile, a particular type of popular assembly was born, made up not only of lords but also of commoners summoned from towns and counties. Superimposed upon an existing tradition of great council meetings, in which king and barons talked together (hence ‘parliaments’), this new ‘borough and shire’ grouping was to become a standard part of the political landscape under Edward I. It remains even now the bedrock of the bicameral British Parliament. Behind all of this there stood the terrifying figure of Simon de Montfort, Earl of Leicester.

The son of a fanatic who had led a crusade against heresy in Toulouse, Simon was a Frenchman native to Montfort-l’Amaury, just to the west of Paris. An almost exact contemporary of King Henry III, he spent much of the first fifty years of his life in Languedoc, Gascony or