As usual, the initial fighting broke out in the west. Henry de Montfort scored an early triumph by bottling up Edward in Gloucester, but then unwisely accepted his cousin’s call for a truce. He had no sooner withdrawn his forces when Edward sacked the town and slipped away, causing Simon to bitterly reproach his son. The king meanwhile began gathering a large army at Oxford, where one of his first acts was to expel the student population. His intention, he explained, was to protect them from the savagery of his Scottish allies, but in fact he was clearly miffed by their true sympathies. Henry’s growing strength allowed him to brush aside a last-ditch offer by his opponents to respect Louis’ ruling on every point except the alien officials. The advantage was all his after he seized the Montfortian stronghold of Northampton, which was betrayed by local clergymen. The loss was devastating. Among the eighty barons and knights made prisoner were the younger Simon and many leading members of the movement. Montfort refused to despair. “War is such that the advantage first goes to these, then to those,” he declared and followed up by predicting that the enemy would be consumed by fear and confusion before May was out. London, however, was gripped by panic as word spread it was about to be betrayed like Northampton, resulting in the plunder and massacre of the Jews. As royalist forces burned and butchered their way through local hamlets, Simon attempted to draw them south by laying siege to their garrison in Rochester, whose inhabitants were subjected to a similar bloodletting. With barely London left to the reformist party, Simon gambled everything on seeking out and giving battle to the king. The two sides squared off in Sussex, with the royalists encamped in and around the village of Lewes and the Montfortians eight miles away in Fletching. Simon sent his bishop friends to Henry to reiterate his offer of peace if the king would observe only the provision prohibiting alien officials, sweetening it now to include 30,000 marks in compensation. Henry was inclined to accept, but Richard, aggrieved that his property had been ransacked, was against it, as was Edward. The one-time idealist and reformer declared that peace was only possible if his uncle and the others came to them with halters around their necks.
A truce was to be observed during the course of arbitration. Henry being Henry, he ordered Roger Mortimer, an exceedingly violent man even for a marcher baron, to attack Simon’s manors in the hope of preventing his adversary from attending the proceedings in person. He knew the reformist side hinged on Montfort’s powers of persuasion and his friendship with Louis. In the end, all it took was a hole in the ground. While heading south for Dover, Montfort suffered a broken leg when his horse stumbled and fell. Forced to stay behind, he was no doubt confident the king of France would still rule close to his original affirmation of the Provisions. Louis, however, stunned everyone by completely nullifying them in his Mise of Amiens issued on 23 January 1264. Acting “unmindful of his own honour,” in the words of one chronicler, he declared that Henry had the right to appoint any official he saw fit, whether native-born or not. He tried to evade responsibility by insisting that the pope had nullified the Provisions first, then hedged by assuring the people of England that Magna Carta was in no way affected by his ruling. Sworn to abide by the award, Simon and his associates justified their continuing resistance by arguing that the Provisions were founded on the principles of Magna Carta. Louis’ betrayal, which was variously attributed to bribes, nagging or some concerted action with the papacy, rankled deeply. “Though all may forswear me, I will stand firm with my sons in the just cause to which my faith is pledged,” Simon proclaimed, adding gloomily that of all the lands he had been to, never had he met with more treachery than in England. But he did get some help when Gilbert de Clare finally decided to join forces with him and London remained firmly committed to the reformist cause. Civil war was now inevitable.
Roger Bigod assured Henry he was not. They asked only for the removal of the aliens and establishment of a council of 24 to guide the king in reforming the government. Henry was allowed to name half the members of the council and true to form he included two of his brothers in the list. The next parliament convened on 11 June in Oxford, with the barons again arriving armed to the hilt. Ostensibly this was a war parliament in preparation for moving against the Welsh, but the barons suspected the king and Lusignans might try to ambush them with foreign mercenaries. Dubbed by later royalists as the “mad” parliament, the barons submitted a petition to the king that called for sweeping changes in the way the monarchy operated in England. A permanent council of fifteen would henceforth advise the king in all matters of appointment, policy and patronage; parliament would meet three times a year at fixed dates, not at the king’s pleasure; and the crown would resume control over all its castles currently in the hands of aliens, which was more or less all of them. As an alien, Simon de Montfort willingly offered up his two castles, but his archenemy William de Valence refused. “Thy castle or thy head, William,” Simon warned him. Parliament broke up during the noonday lunch when the brothers stole away for the coast. Not taking any chances, the barons took off in pursuit and caught up with them at Aymer’s residence in Winchester. Riding with the baronial party, Henry and Edward managed to cut a deal for their safe conduct out of the country. At this stage the king could no more control the course of events than he could the weather. The next month the royal barge was caught in a storm on the Thames. Fearing thunder and lightning as he did, Henry ordered the boat docked at the nearest abode, which happened to be the Montfort summer residence. Simon went out to greet his majesty with all due respect, but Henry shuddered at him in terror. “Never fear, my lord, the storm has passed,” Simon reassured him. “True, but I fear you more than all the thunder and lightning in the world!”