|The World of Ice & Fire (mentioned)
King Morgon and his thralls were defeated in a twenty-years-long war with King Loreon I of House Lannister. According to a semi-canon source, Morgon was said to have been a powerful necromancer who cursed his vanquishers as he died, claiming he would return from the grave. In response, Loreon had Morgon's body cut into pieces and fed to his lions. Two years later the lions broke free within Casterly Rock, slaying three of Loreon's sons.