This Monday, June 15, is the 800th anniversary of the signing of the Magna Carta (Great Charter).
At Runnymede, about 20 miles outside London, the barons forced King John of England to sign an agreement that represented a profound break in English history.
King John believed that he governed by divine right, that God had given him power to make law. He was literally above the law and able to define it. According to this theory, there were no limits on his authority.
Because John had fought a series of losing wars, he had lost prestige and was in desperate need of money.
The barons were tired of what they saw as a weak and incompetent King wasting their money on badly executed foreign campaigns. They insisted that in return for the money he needed, he would concede three key principles.
First, they insisted on the right to trial by jury which implied that juries could defy the King and find people innocent even if he wanted them punished.