Scenario: William the Even Younger King. Might be a bit crackpot.
Henry 'the Young King' III, King of England (b.1155: d.1183) m. Margaret, Princess of France (b.1158: d.1177) (a), Gisela of Swabia (c.1168: d.1184) (b)
1a) William III, King of England, Duke of Normandy and Aquitaine, Count of...