Magna Carta Libertatum, commonly called Magna Carta or sometimes Magna Charta, is a royal charter of rights agreed to by King John of England at Runnymede, near Windsor, on 15 June 1215. First drafted by the Archbishop of Canterbury, Cardinal Stephen Langton, to make peace between the unpopular king and a group of rebel barons, it promised the protection of church rights, protection for the barons from illegal imprisonment, access to swift and impartial justice, and limitations on feudal payments to the Crown, to be implemented through a council of 25 barons. Neither side stood by their commitments, and the charter was annulled by Pope Innocent III, leading to the First Barons' War.

A royal charter is a formal grant issued by a monarch under royal prerogative as letters patent. Historically, they have been used to promulgate public laws, the most famous example being the English Magna Carta of 1215, but since the 14th century have only been used in place of private acts to grant a right or power to an individual or a body corporate. They were, and are still, used to establish significant organisations such as boroughs, universities and learned societies.