Things were looking bleak for Henry in early 1258. Three years of famine, disease among the cattle and rising food prices compounded problems with the papacy and Henry’s magnates. When parliament met on 9 April, they were in far from compliant mood. Murmurs of dissent were beginning to increase among the magnates, some of whom had been drawing up plans for reform. Henry’s money problems, notably for Sicily, brought further request for aid from the papal visitor, this time for 1/3rd of all moveables and immovables, an amount hitherto unheard of. Two days after the request, on 30 April, the king was startled by the appearance of the lords at Westminster in armour, though leaving their swords at the door. When Henry asked their leader, Roger Bigod, ‘what is it, my lords? Am I your prisoner’ they responded with courtesy. Yet for the king, things had now reached a watershed. Over the coming days, Henry and the prince agreed to what later became known as the Provisions of Oxford.
The key developments were that a 24-man council be appointed, half chosen by the king, half by the opposition, led by Simon de Montfort. After Henry reluctantly agreed, the barons met at Oxford on 11 June to ensure its implementation. A list of grievances was presented and the temporary council of 24 appointed. Among its actions was to put forward preparations for the establishment of a permanent 15-man council. Parliament was to meet three times every year, including the 15-man council and a separate committee of 12, responsible for discussing the actions of the 15. An independent body of 24 was also selected to arrange a one-off aid. For the first time in 24 years a party existed to be responsible for national government. Its style was oligarchic, rather than the previous arrangement where the king ruled without a senior magnate. A justiciar, treasurer and chancellor were all chosen, while sheriffs were appointed to hold office for only one year at a time.
Among the early actions was the requisition of the royal castles, due to be held by castellans for 12 years. Not surprisingly, this action infuriated Henry’s royal favourites, notably William de Valence who took refuge at Wolvesey Castle near Winchester Cathedral. Valence surrendered on 5 July and headed abroad. The following month, Henry agreed again to the rights of the 24 and did so again in October. When Richard, now King of the Romans, returned to England in January 1259, he was allowed re-entry to England only on condition that he swore an oath to uphold the Provisions of Oxford.
Peace with Wales was followed by the Treaty of Paris in 1259, during which Henry agreed to give up much of his birthright in Poitou, Normandy and Anjou in exchange for certain courtesies. Relations with Louis had improved, thanks to the work of Simon de Montfort. Henry returned to England early in 1260 with hopes still of acquiring Sicily for Edmund.
In England, many of the opposition were growing restless with the lack of progress in implementing reforms since the agreement of the Provisions of Oxford. The Earl of Gloucester was increasingly alienated from Simon. Late 1259 saw Edward take up the wishes of the opposition and pass the Provisions of Westminster. Before Henry’s return, news reached him that Edward was in league with Simon. On his return, Henry took up accommodation at St. Paul’s while the Earl of Gloucester, recently returned from France, sought to advance on the city. Both Henry and Simon had good armies, but Henry’s reconciliation with Edward brought his alliance with Simon to an early end.
Henry’s desire to escape from the Provisions of Oxford finally came to fruition in June 1261 after obtaining papal bulls from Pope Alexander IV which declared the provisions null and void, following which Henry sacked the justiciar. In January 1262 he wrote to the new pope, Urban IV, asking for clarification of the continuing validity of the papal bulls and soon received confirmation. In an attempt to resolve his feud with Simon, it was decided that the matter should be put forward to the arbitration of Louis. As troubles with Wales escalated, Henry agreed to the provisions, though also sending word to Louis regarding his desire for the conditions to be placed under the arbitration of the French king. As Henry’s health weakened in March 1263, he ordered an oath of allegiance to be taken to Edward as his rightful heir. In July he agreed to the mediation of Cornwall, aliens were banished back to Poitou and the justiciar reappointed. In October Henry and Simon finally sailed to France for arbitration, but returned without progress. As things continued to heat up in parliament, Henry again crossed to France in December, this time without Simon who had been injured after falling from his horse. At the end of 1263, Louis agreed that the provisions of Oxford were illegal and the award known as the Mise of Amiens made in January 1264.