The significance of the Magna Carta, signed in 1215, lies in its establishment of the principle that no one, not even the king, is above the law. This foundational document limited the powers of the monarchy and ensured certain legal rights for subjects, including the right to a fair trial. The Magna Carta laid the groundwork for modern democratic principles and inspired future constitutional developments, including the English Bill of Rights and the U.S. Constitution. It symbolized the early struggle for individual rights and governance based on consent, which influenced political thought for centuries to come.