Why did English nobels force King John to sign the Magna Carta?

Kingh John had many enemies. He was tyrannical and considered by most to be an unjust king. The nobles rebelled against the large taxes levied upon them by the king, and they took over London. They even attempted to capture the king. As a result, the Archbishop of Canterbury write the Magna Carta to protect the rights of the nobility and the church in the hopes of making peace between the king and his subjects. King John signed the Magna Carta under duress, and sadly, neither side kept their end of the bargain. In the end, Pope Innocent III annulled the charter, an act that led to the First Baron's War.