He also agreed to live thriftily till his debts were paid, and to leave his sons as hostages with Earl Simon.
Simon at once set about the work of reform.

The King's Standing, or Privy, Council was reconstituted, and the Parliamentary Commissioners were abolished, "for Simon held it as much a man's duty to think and work for his country as to fight for it." A marked difference is seen between Simon's policy at Oxford and the policy after Lewes.

The Provisions of 1258 were restrictive.

The Constitution of 1264 deliberately extended the limits of Parliament.

"Either Simon's views of a Constitution had rapidly developed, or the influences which had checked them in 1258 were removed.
Anyhow, he had genius to interpret the mind of the nation, and to anticipate the line which was taken by later progress."[20] What Simon wanted was the approval of all classes of the community for his plans, and to that end he issued writs for the Parliament--the _Full Parliament_--of 1265.
The great feature of this Parliament was that for the first time the burgesses of each city and borough were summoned to send two representatives.