A long time ago, and still in some places today, there was this one guy who could do anything he wanted—take people's stuff, take people's homes and land, kick people out of the realm, even kill people. There were really no limits to that one guy's power.
That guy might be called a czar or an emperor or a king. He might happen to be a good guy, a kind man, someone who doesn't go around hurting people without good reason—but, on the other hand, he might be a bad guy, a cruel man, someone who destroys people's lives just because he lost his temper.
In England, the guy with all this ultimate power was the king. There were no laws that limited the king's power—and if he didn't like a law, he could just shrug and change it. But on this date in 1215, this changed.
That's when English barons forced on King John a written document we now call the Magna Carta (“Great Charter”). This document stated that the king couldn't punish “freemen” except through the law of the land. This is an earlier version of the Fifth Amendment of the U.S. Constitution, which states that no person shall be deprived of life, liberty, or property without due process of law.
After the Magna Carta, English kings could no longer wave their pinkie fingers and order someone banished or executed. Kings could no longer be completely arbitrary about grabbing desirable women and horses and estates. Basically, the Magna Carta meant that the king (or queen) had to follow the law, too.
In England (in Egham, Surrey), Magna Carta Day is celebrated with music and amusement rides and clowns and other festivities.
If the king had ultimate power...
You may be wondering how the barons “forced” King John to accept the Magna Carta, if the king had so much power. Well, kings and emperors and other absolute rulers have always had one weakness—which is that their people might and often did rise up in rebellion against them, throw them out of power, kill them, and put someone else on the throne. It seemed as if this is what would happen in that long-ago time in England: for years the barons under King John's unpopular rule conspired to rebel against him. But there was no obvious person to take the throne if their rebellion succeeded. Nobody could agree about who would be a good alternative to King John. Eventually the barons decided to rise up but then force the king to give them rights and protections. If King John hadn't accepted the Magna Carta, he would have been deposed and quite likely killed.
So he gave in, and democracy got a strong push in the right direction—or should I say the “rights” direction?
Also on this date: