What is the main reason for the magna carta?

The main reason for the Magna Carta, signed in 1215, was to limit the powers of King John of England and establish certain legal rights for his subjects. It arose from widespread discontent among the barons due to heavy taxation, arbitrary justice, and military failures. The Magna Carta aimed to protect the privileges of the nobility and ensure that the king could not act without legal consent, laying the groundwork for the principles of due process and the rule of law.