The Magna Carta, signed in 1215, was significant for British constitutional law as it limited the powers of the monarchy and established the principle of legal rights for individuals. This charter, agreed upon by King John, mandated that no free man could be imprisoned or stripped of his rights without due process. It laid the groundwork for the development of parliamentary democracy and the rule of law in England. Over time, the Magna Carta has become a symbol of liberty and justice, influencing legal systems around the world and serving as a foundational document for modern democratic governance.