Magna Charta

Magna Charta, “the great charter,” extorted from King John by the barons of England at Runnymede on June 5, 1215, that guaranteed certain rights and privileges to the subjects of the realm, which were pronounced inviolable, and that established the supremacy of the law over the will of the monarch.

Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)