The Magna Carta, signed in 1215, is a cornerstone document in the history of human rights and constitutional law. It established the principle that everyone, including the king, is subject to the law. This document limited the power of the monarchy, granting certain legal rights to subjects and laying the groundwork for the development of parliamentary democracy. It emphasized the importance of due process and the right to a fair trial, concepts which have influenced modern legal systems and human rights declarations worldwide, making it a significant milestone in the evolution of individual liberties.