Edward, Prince of Wales, stood by the Provisions of Oxford for a few years, but supported his father when the latter refused to re-confirm the Provisions in 1263.

As a last resource to prevent civil war, Simon and Henry agreed to appeal to King Louis of France to arbitrate on the fulfilment of the Provisions.

The Pope had already absolved Henry from obedience to the Provisions, and the Award of Louis, given at Amiens and called the _Mise of Amiens_, was entirely in Henry's favour.

It annulled the Provisions of Oxford, left the King free to appoint his own ministers, council, and sheriffs, to employ aliens, and to enjoy power uncontrolled.
But the former charters of the realm were declared inviolate, and no reprisals were to take place.
To Simon and most of the barons the Award was intolerable, and when Henry returned from France with a large force ready to take the vengeance which the Award had forbidden, civil war could not be prevented.

London rallied to Simon, and Oxford, the Cinque Ports, and the friars were all on the side of the barons against the King.
On May 14th, 1264, a pitched battle at Lewes ended in complete victory for Simon, and found the King, Prince Edward, and the kinsmen and chief supporters of the Crown prisoners in his hands.
Peace was made, and a treaty--the _Mise of Lewes_--drawn up and signed.
Once more the King promised to keep the Provisions and Charters, and to dismiss the aliens.