It seems like you're referring to the Magna Carta, which was indeed signed in 1215. The Magna Carta (Latin for "Great Charter") was a pivotal document in English history, establishing the principle that everyone, including the king, was subject to the law. It laid the groundwork for many legal rights and helped to establish foundational concepts of democracy, such as due process and the right to a fair trial.
The Magna Carta arose from the grievances of the barons against King John, who was perceived as a tyrannical ruler. The charter sought to limit royal authority and protect the rights of the nobility, but its principles eventually came to be understood as rights applicable to all citizens.
Over the centuries, the Magna Carta has been interpreted and reinterpreted, influencing various democratic movements and legal systems around the world. It stands as a symbol of the struggle for individual rights and the rule of law. If you have specific aspects you'd like to explore further, feel free to ask!