When Richard the Lionheart died in 1199, his son John took the throne. He lost Normandy and tried to conquer it back with the help of increased taxes. King John’s actions deeply upset the lords, leading them to pressure him into signing the Magna Carta in 1215. Which was basically an updated version of the Charter of Liberties from 1100. Under pressure, King John first signed the Magna Carta but then went back on his word, plunging the country into the First Barons’ War. He died from dysentery a year later, and his young son succeeded him. The Magna Carta was approved by the people looking after his son, and later by King Henry in 1225 when he grew up.
It laid the foundation for an independent church, prioritized the law, and set boundaries on royal power. Fast-forward to 1957, and we find the American Bar Association acknowledging the Magna Carta’s influence on the U.S. Constitution.
The 1297 version of the Magna Carta is still a part of English law.