The first to sign the Magna Carta, which limited royal power, was King John of England in 1215. The document, also known as the Great Charter, was signed after a rebellion by a group of barons who sought to curtail the king's arbitrary authority and protect their rights and privileges. It established the principle that everyone, including the king, was subject to the law, and laid the groundwork for future constitutional governance. The Magna Carta is often celebrated as a foundational step towards democracy and has influenced legal systems around the world, highlighting the importance of individual rights and due process.