In spite of these murmurings, and in spite of the king's attempts to shake off the control which had been imposed on him, the Provisions of Oxford were observed for four years. But Henry was preparing to tear himself free as soon as possible. He sent privately to Rome and got absolved from his oath by the Pope. He courted those who were jealous of Earl Simon, and he encouraged many of his foreign relatives and dependents to creep back to England. In 1261 he felt strong enough to break loose, seized the Tower of London, and raised an army. But he found himself too weak, dared not come to blows with the adherents of the Provisions of Oxford, and again consented to place himself in the hands of the guarantors. But as disputes about his conduct continued to arise, he offered to submit his rights, and those of the barons, to the arbitration of his neighbour, St. Lewis of France, whose probity was recognized by all the world. Simon and his friends consented--an unwise act, for they might have remembered that the French king was not well acquainted with the constitution or the needs of England. By a decision called the _Mise of Amiens_, from the city at which it was proclaimed, St. Lewis announced that Henry ought to abide by the customs stated in Magna Carta, but that he need not keep the Provisions of Oxford, which were dishonourable to his crown and kingly dignity (1263). [Sidenote: =Civil war breaks out.=] The Mise of Amiens precipitated the outbreak of civil war, for Simon and his party refused to accept the decision which had been given against them, though they had promised to abide by it. This flinching from their word alienated from them many who would otherwise have taken the side of reform, and it was felt that a grave responsibility lay on Simon for striking the first blow. Hence it came to pass that the king was supported by a larger party than might have been expected. His own brother and son, Richard of Cornwall and Prince Edward, who had hitherto usually leaned to the party of reform and striven to guide him towards moderation, now supported him with all their power. The Earls of Norfolk and Hereford and many other great barons also took arms in his favour. Earl Simon, on the other hand, was helped by the Earls of Gloucester and Derby, and enthusiastically supported by the citizens of London, who had been maddened by the king's arbitrary taxes. [Illustration: BATTLE OF LEWES.] [Sidenote: =Battle of Lewes.--The Mise of Lewes.=]