Previous king: Richard I (brother) Reigned: 1199-1216 Next king: Henry III (son)John was the youngest son of Henry II. He was an unpopular king. He rebelled against his brother Richard I, but Richard eventually forgave him and made John his heir. However, when John became king, his barons rose against him, and forced him to sign the Magna Carta at Runnymede in 1215. This was a document giving all freemen of the kingdom certain rights, and limiting the power of the king (see right). With Magna Carta, John placed himself and England's future sovereigns within the rule of law. This meant that kings should no longer do whatever they wanted.