Second Barons' War

Causes

The reign of Henry III is most remembered for the constitutional crisis in this period of civil strife, which was provoked ostensibly by Henry III's demands for extra finances, but which marked a more general dissatisfaction with Henry's methods of government on the part of the English barons, discontent which was exacerbated by widespread famine.

French-born Simon de Montfort, Earl of Leicester, had originally been one of the foreign upstarts so loathed by many lords as Henry's foreign councillors, but having inherited through his mother the English title Earl of Leicester, he married Henry’s sister Eleanor without Henry's permission, and without the agreement of the English Barons (ordinarily necessary since it was a matter of state). As a result, a feud developed between de Montfort and Henry. Their relationship reached a crisis in the 1250s, when de Montfort was put on trial for actions he took as lieutenant of Gascony, the last remaining Plantagenet lands across the English Channel.

Henry also became embroiled in funding a war against the Hohenstaufen Dynasty in Sicily on behalf of Pope Innocent IV in return for the Hohenstaufen title King of Sicily for his second son Edmund. This made many barons fearful that Henry was following in the footsteps of his father King John and, like him, needed to be kept in check. When Henry's treasury ran dry, Innocent withdrew the title, and in regranting it to Charles of Anjou in effect negated the sale.

Simon de Montfort became leader of those who wanted to reassert the Magna Carta and force the king to surrender more power to the baronial council. In 1258, initiating the move toward reform, seven leading barons forced Henry to agree to the Provisions of Oxford, which effectively abolished the absolutist Anglo-Norman monarchy, giving power to a council of twenty-four barons to deal with the business of government and providing for a great council in the form of a parliament every three years, to monitor their performance.

Henry was forced to take part in the swearing of a collective oath to uphold the Provisions of Oxford. In the following years, those supporting de Montfort, including his circle of Franciscan advisors centered on Adam Marsh, and those loyal to the king grew more and more polarised; Henry obtained a papal bull in 1261 exempting him from his oath, and both sides began to raise armies, with the Royalists army under the control of Edward Longshanks, Henry's eldest son. Armed conflict soon followed.

Course of the war

The charismatic de Montfort and his forces had captured most of southeastern England by 1263, dispossessing royalists like Roger Bacon's family and granting their estates to supporters of de Montfort's cause. At the Battle of Lewes in 1264, Henry was defeated and taken prisoner by de Montfort's army. While Henry was reduced to a figurehead king, de Montfort broadened parliamentary representation to include groups beyond the nobility, members from each county of England and many important towns. Henry and Edward continued under house arrest. The short period which followed was the closest England was to come to complete abolition of the monarchy until the Commonwealth period of 1649–1660, and many of the barons who had initially supported de Montfort began to suspect that he may have gone too far with his reforming zeal.

Only fifteen months later de Montfort's gains were reversed when Edward Longshanks escaped captivity to lead the royalists into battle again, defeating and killing de Montfort at the Battle of Evesham in 1265. His son, Simon, attempted a negotiated surrender but it was rejected by de Montfort loyalists. The impasse culminated in the six-month Siege of Kenilworth at which the King prevailed. De Montfort's forces were permitted to leave the castle with their weapons and horses.

Following this victory, savage retribution was exacted on the rebels and authority was restored to King Henry. The casualties of the war are estimated at 15,000.

Timeline