William X The Toulousan of Aquitaine, Duke of Aquitaine
Burke says he died in 1156. Some call him William VIII.
John of Gaunt Plantagenet, Duke of Lancaster
and Earl of Richmond. Some say born Jun 1340, but see CP vol.XIV,p.421. Earl of Derby, Lincoln. Duke of Aquitaine. Lord of Beaufort & Nogent. Burke says he died at Ely House, Holborn King of Castile & Leon. Lord of Bergerac & Roche-sur-Yon. The Complete Peerage vol.VII,pp.410-416 & vol.XIV,p.421.
Catherine Swynford Roet
Governess to the Dukes daughter by his first wife, became John's mistress in
1388. All their children were before they were married. They were ligitimated
later by the Pope.