Magna Carta is a legal document that was signed by King John of England in 1215. It is considered as one of the most important documents in history, as it established the principle that everyone, including the king, was subject to the law and had certain rights that could not be violated. The phrase "Magna Carta" means "Great Charter," and it outlined specific protections for individuals, such as protection from unlawful imprisonment and the right to a fair trial. It also established the principle of limited government and the rule of law, which has had a significant impact on legal systems around the world.