The Nobles made King John sign the document known as the Magna Carta, meaning Great Charter. This changed some certain rights. Before, the king could put anyone in jail without a cause or reason. But on the Magna Carta, there was the Habeas Corpus, which meant you have to have a reason to keep a person in jail. One of the more important laws was that even the King had to obey the law. This idea became one of the basic principles of English Government. - I hope this helps :)