The Magna Carta, signed in 1215, was a pivotal document in limiting the power of the English monarchy. It established the principle that everyone, including the king, was subject to the law. By ensuring certain legal rights to the barons and, by extension, to free men, it curbed arbitrary royal authority. The Magna Carta introduced concepts of due process and the right to a fair trial, which laid the groundwork for the development of constitutional law. Ultimately, it was a milestone that influenced democratic principles and legal systems not only in England but also across the world in subsequent centuries.