The Provisions of Oxford
are often regarded as England's first written constitution (although the Magna Carta and earlier law codes such as that of King Æthelberht of Kent are also significant).
Installed in 1258 by a group of barons led by Simon de Montfort, 6th Earl of Leicester, the provisions forced King Henry III
of England to accept a new form of government. The power to decide the form of this government was placed in the hands of a council of twenty-four members, twelve selected by the crown, twelve by the barons. The twenty-four members selected were to pick four men among them (two chosen from the monarch's side by the community members and vice versa) who created, in turn, a 15-member Privy Council to advise the king and oversee the entire administration. The selected men were to supervise ministerial appointments, local administration and the custody of royal castles. Parliament, meanwhile, which was to meet three times a year, would monitor the performance of this council.
A written confirmation of the agreement was sent to the sheriffs of all the counties of England in Latin, French and, significantly, in Middle English. The use of the English language was symbolic of the Anglicisation
of the government of England and an antidote to the Francization which had taken place in the decades immediately before. The Provisions were the first government documents to be published in English since the Norman Conquest
two hundred years before.
The Provisions of Oxford were replaced in 1259 by the Provisions of Westminster
. These Provisions were overthrown by Henry, helped by a papal bull, in 1261, seeding the start of the Second Barons' War (1263–1267), which was won by the King and his royalist supporters. In 1266 it was annulled for the last time by the Dictum of Kenilworth
The 1258 Provisions had a significant effect upon the development of the English Common Law system. In and after the reign of Henry II the number of available 'writs' (recognised causes for legal action in the common law courts
in London) had grown. This expansion of jurisdiction by the royal courts aroused so much resentment that the 1258 Provisions of Oxford provided that no further expansion of the writ system would be allowed.