Richard I succeeded Henry II. He spent less than a year of his reign in England because he left for the Holy land to take part in the third crusade. During his absence , his brother John tried to usurp his place. When Richard died , the English and Norman barons chose John to be king. In the popular perception , John is "Bad king John " . He abused of the feudal system ,he urged land and profits of the barons. There was a rebellion and so John agreed to sealed the Magna Carta.
The magna carta was written in 1215 and had a number of inducements against John's rule. For example the king couldn't imprison illegally, he couldn't take off the private property ; he could administrate swift justice. There was a committee of 25 barons to oblige the king to respect the agreement.
Habeas corpus is a written document and legal action to determinate the legality of detention.
Habeas corpus was very important because it represented a protection against the king and barons . Today habeas corpus is still a protection against the state.