King John's father, Henry II, introduced extensive judicial reforms, established the authority of the royal courts and laid firm foundations for the future system of justice in England.
In contrast, King John regularly abused the justice system to suppress his opponents and to extort revenue from the barons.
The justice system and the feudal system were the two main themes in Magna Carta, but the most famous clause dealt with justice:
No free man shall be seized or imprisoned, or stripped of his rights or possessions, or outlawed or exiled, or deprived of his standing in any other way, nor will we proceed with force against him, or send others to do so, except by the lawful judgement of his equals or by the law of the land.
The barons ensured that numerous other clauses in Magna Carta defined in more detail how the justice system and its officials were to operate. These clauses sought to remedy specific abuses by the king and to make the system more consistent, accessible and fair.