When King Richard I ruled England he had no legitimate heirs. King John was his successor, but there was a problem with the young Arthur who was the son of Richard's and John's brother Geoffrey who was older than John. Following rules of succession, Arthur should of been crowned king instead of John. However King Richard I feared that Arthur was too young and under too much influence of the French king, so he made John his heir instead. King John eventually had Arthur imprisoned, and he vanished after a certain point. Most believe that he was murdered on King John's orders.