Men in England are talking about reform because they dislike paying for Henry III’s misguided foreign adventures, and they are incensed at the corruption of Henry’s sheriffs who are extorting funds and obstructing justice. Henry ignores them and repeatedly refuses to support the justice and liberties established in Magna Carta.

Simon de Montfort enters the fray to support reform for personal reasons and for reasons of principle. Personally he is tired of the king, who is also his brother-in-law, not paying him what he owes him. Montfort is a superb soldier, a cosmopolitan who is also religious, an educated man who discusses the mathematical basis of the world with Bishop Grosseteste, and reads Grosseteste’s essay on tyranny. A family man who adores his wife and his sons, it takes Montfort some time to realize that his conflict with the king is based on more than personal betrayal. He realizes he must confront the king on principle.

The Montforts and a host of barons, knights, merchants, and clergy stop Henry III's advance toward power by balancing it with incorruptible sheriffs and a powerful council to advise the King. They compel Henry to sign the Provisions of Oxford (1258) and lay the foundation for "Parliament". The implications for representative government are momentous.

Henry III gnaws and tunnels “like a rat,” trying to undermine the Provisions. Prince Edward, his son and heir, uses bribes and gifts to seduce reformers. The King dissolves the Council, tears up the Provisions and fields an army.

Simon and the young bachelor knights rush to protect the reforms. Peter de Montfort is captured in Northampton, but Simon meets the King and Prince at the Battle of Lewes, and captures them. However, winning is one thing. Building on that victory is another.

Simon de Montfort is not a perfect man. He has a hot temper and the energy of a thunderbolt. He despises men who will not keep their word, yet his own reputation is shadowed by his willingness to keep captured land and castles as a payment for the money the king did not pay him, and to give them to his wild sons.

To his credit Montfort never hurts Henry III or Prince Edward while he has them captive. When they refuse to affirm the principles of liberty and justice embodied in Magna Carta, so Montfort daringly calls a parliament and invites the people to attend. He sends messengers to every county and many cities and towns, asking them to send two elected representatives to a parliament.

For the first time, men across England vote in parliamentary elections. (In the counties they have to meet a 40-shilling property qualification. In the towns there are different voting requirements.) Representatives of the yeomen of the shires and the people of the big towns join archbishops, bishops, earls and barons on January 20, 1265, in Parliament. Nothing like it has been seen since Rome was a republic thirteen hundred years earlier.

Prince Edward escapes, and breaks his sworn word to support the reforms. He gathers an army to destroy the reformers. Ransomed from prison, Peter de Montfort rides to the side of Simon de Montfort. They and a group of young bachelor knights vow to defend the reforms. Among the young knights are Simon de Montfort’s sons and Peter’s son Piers.

In August the Montforts and the bachelor knights camp in the Vale of Evesham, close to Evesham Abbey. They are on their way to London, where support for reform remains strong. Travelling with them is Henry III. They treat him with exquisite courtesy while he remains their prisoner. On 4 August 1265, Prince Edward and his army surprise and surround them.

Simon de Montfort refuses either to exploit the captive King as a pawn or to use the abbey for military purposes. He urges the young bachelor knights to escape and support the reforms at another time and place. They refuse to desert him.

The day darkens as a storm moves in. Montfort saddles up, and faces the army moving in to crush the reformers. "They have our bodies," he says calmly. "God has our souls." He spurs his horse into battle.

Simon, Peter and the bachelor knights fight valiantly against the overwhelming force of Edward's army. Simon and Peter are killed, as are Simon's sons. Peter's son Piers is wounded. At Prince Edward's orders, Simon de Montfort's body is hacked into pieces, and buried in different parts of the kingdom, to avoid founding a martyr's grave and pilgrim site.

We may wonder why the Montforts did not surrender, but chose to die defending the cause of reform. Did they guess that Edward would hang them if they surrendered? Did they believe that some things are worth dying for? (“Unless a grain of wheat falls into the earth and dies, it remains by itself alone, but if it dies, it bears much fruit.” John 12:24)