At the head of the barons, in their resistance and indignation against foreigners, was Simon, earl of Leicester, himself a foreigner. The youngest son of Simon of Montfort, the persecutor of the Albigenses, he had inherited the earldom of Leicester through his mother, and had recovered his property, which had been confiscated in 1232, through the favor of King Henry, who had taken a fancy to the young Provençal, whom he had aided in marrying his sister Eleanor, widow of the Earl of Pembroke, to the great indignation of the royal family and the nobility of England.
The favor of the king was short-lived. Montfort had initiated himself into the good graces of the barons, who had been so violently opposed to him at first; and the king, jealous and uneasy, drove him from England in 1239, scarcely allowing the earl time enough to embark with his wife, who went with her husband to France. He left her, to assume the cross and proceed to Palestine, where he distinguished himself by glorious feats of arms. On his return, the king had forgotten his jealousy and anger. The earl lived peaceably in England, and was even raised to the dignity of Governor of Gascony. He was recalled in 1252, under the pretence of misbehavior, and young Prince Edward was provided with the office thus snatched from the Earl of Leicester, who grew more and more attached to the cause of the refractory barons, of whom he became the real chief.
The king's disorderly habits and want of foresight having at length reduced him to the last extremities, he decided on confronting the Parliament assembled at Oxford on the 11th of June, 1258. The whole town was filled with men-at-arms; all the barons had brought a numerous following with them. They presented to the king the list of the council who were to be entrusted with the administration of the kingdom. Twelve members were to be elected by the king, and twelve by the barons. This assembly, presided over by the Earl of Leicester, was to be invested during twelve years, with the care of the royal castles. No expense could be incurred against their will; they held possession of the great seal, and were to revise the accounts of the chancellor and of the treasurer; the king was to be compelled to convoke Parliament three times a year.
Henry agreed without hesitation to these humiliating conditions, just as his father. King John, had signed Magna Charta. Prince Edward, whose conscience would not allow him to take oaths as lightly as his father had done, at first made a show of resistance, but ended by acceding to the wishes of the barons. His cousin Henry, son of Richard of Cornwall, who was then known as the King of the Romans, declared that his oath would not be valid, if made in the absence of his father. "Let your father have a care," said Leicester, "if he refuse to do the bidding of the barons of England, for, in that case, he shall not remain in possession of one foot of land in the kingdom." The young nobleman accordingly took the oath.
The king's brothers had refused to give up the castles which they occupied. "I will have them, or you shall lose your head," Montfort declared to William of Valence. And he made such formidable accusations against them at the council, that the four brothers took refuge in Wolesham Castle. The barons pursued them, made them prisoners, and sent them out of the kingdom. The acts of the Parliament of Oxford, the "Mad Parliament," as the royalists called it, were strictly observed throughout the kingdom.
The barons had taken every precaution against a feeble or improvident government; but they had not been able to guard against the temptations of triumphant ambition. The offices left vacant after the departure of the king's favorites, were filled up by the favorites of the Earl of Leicester. His allies began to grow alarmed at his great power; the King of the Romans, who had recently returned to England, after having taken the oath of allegiance to the acts of the barons, endeavored to create rivals to the Earl. The barons, violent and haughty, insulted the king and oppressed the people. "Why are you so bold with me, my lord, earl?" said Henry to Roger Bigod; "do you not know that I could order all your corn to be destroyed?" "Indeed, sir king," said the earl, "and could I not send you the heads of the destroyers?"
The dissensions among the barons reawakened the hopes of the king. He had provided himself with a dispensation from the Pope, which relieved him of his oaths, and, in February, 1261, he ventured to announce to the barons that they had greatly abused their power, and that he, the King of England, intended for the future to govern without them. He had at the same time taken possession of London. Prince Edward, who had recently returned from France, had, on the contrary, tendered his support to the barons, out of respect for his oath, as he said. The king saw a certain number of his adversaries drawing nearer to him, and in spite of the rebellion of the nobility, the temporary success of the king compelled Leicester to escape to France, swearing that he would never again trust to the oath of a perjured sovereign.
In 1263, the struggle had just begun afresh. The Great Earl, as Leicester was called, had raised his standard; the king had taken refuge in London, and Prince Edward was at Windsor Castle. Queen Eleanor, who was even more detested in the city than the king her husband, had endeavored to escape by way of the Thames; the people had recognized her, and her bark had been pelted with mud and stones. Cries were heard of, "Let us drown the witch!" The Lord Mayor of London had some difficulty in protecting her. The king had given up everything and agreed to everything, but only to attack his adversaries again in the month of June, arming himself against them with the Earl of Leicester's claim that the authority of the barons in the government was to be continued after Henry's death, under the reign of his successor. Prince Edward's scruples disappeared before this arrogant audacity, and he openly embraced his father's cause.