King John was forced to sign the Magna Carta because he was facing a rebellion from his barons and nobles who were unhappy with his tyrannical rule and abuse of power. They demanded greater rights and protections for themselves and their property, and the Magna Carta was seen as a way to limit the king's authority and ensure that certain rights and privileges were guaranteed for all free men. By signing the Magna Carta in 1215, King John agreed to abide by certain principles and limitations on his power, although he later sought to annul the document.
