The document signed in 1215 that limited the powers of the English monarchy and established certain legal rights is known as the Magna Carta. This historic charter was agreed upon by King John of England at Runnymede, aiming to address the grievances of his barons who demanded protection against arbitrary rule. The Magna Carta introduced principles such as due process and the idea that no one, not even the king, is above the law. Its legacy has been profound, influencing democratic ideas and legal systems worldwide, and it is often seen as a foundational text in the development of constitutional governance.