Family: 1st Duke of Lancaster John Gaunt Plantagenet / Duchess of Lancaster Katherine de Roet (F1247)
m. 13 Jan 1396-
Male
1st Duke of Lancaster John Gaunt Plantagenet
Birth 14 Mar 1340 Belgium 
Death 3 Feb 1399 Leicester, Leicestershire, England Burial London, England Marriage 13 Jan 1396 Other Spouse Blanche Lancaster | F1246 Marriage 19 May 1359 Reading, Berkshire, England Other Spouse Constanze Castile | F1248 Marriage Sep 1371 Roquefort, Landes, Aquitaine, France Father King of England King Edward Plantagenet, III | F11561 Group Sheet Mother Phillipa de Hainault | F11561 Group Sheet
Female
Duchess of Lancaster Katherine de Roet
Birth 1350 Somme, Picardie, France Death 10 May 1403 Lincoln, Lincolnshire, England Burial Other Spouse Ottes 'Hugh' Swynford | F777 Marriage 1366 Father Mother
Female
Countess of Westmorland Joan Plantagenet de Beaufort
Birth 1375 Anjou, Isère, Rhône-Alpes, France Death 13 Nov 1440 Howden, Yorkshire, England Burial Lincolnshire, England Spouse Knight of the order of the Garter -- 1st Earl of Westmorland, 4th Baron Neville de Raby, Earl Marshal Sir Ralph de Neville, KG | F5083 Marriage 29 Nov 1396 Anjou, Isère, Rhône-Alpes, France