Magna Carta

Cornered by rebellious barons, King John of England was forced to seal Magna Carta, a charter conceding that even the king was bound by law — that he could not tax or imprison at pure whim. It was a self-interested bargain among elites, not a democratic dawn, and John repudiated it within weeks. But the principle it planted — that power has limits above which no ruler stands — slowly grew into the taproot of constitutional government, cited by revolutions and constitutions centuries later.