When King John came to the throne in 1199, he became unpopular for raising taxes to help pay for several unsuccessful wars in France and for interfering too much in the way England was run.
The barons therefore put together an army and sent it to occupy London until the king agreed to meet their demands which would guarantee certain rights and freedoms, including that:
On 19th June 1215 he signed their charter at Runnymede, near Windsor and they agreed to be loyal to him.
The barons called the charter the Charter of Liberties because it guaranteed their freedoms. It was later called the Magna Carta which is Latin for ‘great charter’.