On June 15, 1215, the English King John did what, where?

By the summer of 1215, England's King John was in a desperate situation. His reign had been marked by costly military failures abroad and punishing taxes at home, leading to a massive rebellion by the country's most powerful barons. To avoid a full-blown civil war, John agreed to meet the rebels on neutral ground to negotiate a peace settlement. That meeting took place in a water-meadow by the River Thames called Runnymede, located between the king's castle at Windsor and the barons' stronghold in London.

There, the king was forced to accept the barons' terms, which were written down in a document known as the Magna Carta, or "Great Charter." This charter was less a declaration of universal rights and more a list of specific grievances aimed at limiting the king's absolute power. It established for the first time that the monarch was not above the law, and it guaranteed certain liberties, such as the right to a jury trial and protection from illegal imprisonment.

While King John didn't technically "sign" the document in the modern sense—he authenticated it by affixing his royal seal—his action on that day became a landmark event in the history of constitutional law. Although John tried to have the charter annulled almost immediately, it was reissued by later kings and became a foundational symbol of liberty, profoundly influencing legal systems and documents around the world, including the United States Constitution.