The significance of the Magna Carta for modern democratic principles lies in its establishment of the rule of law and the concept of limited government. Signed in 1215, it curtailed the arbitrary power of the monarch by ensuring that the king was subject to the law. The Magna Carta laid the groundwork for fundamental freedoms, such as due process and the right to a fair trial. Its principles greatly influenced later constitutional developments, serving as a symbol of liberty and a challenge to tyranny in shaping modern democracy.