Constanza married Lancaster, Duke of Lancaster John Sep 1371, , Rochefort-Sur-Me, Charente-Maritim, France. John (son of Plantagenet, King of England Edward III and Avesnes, Queen consort of England Philippa) was born 24 Jun 1340, Abbaye Destbavon, GAND, Flandreorientale, Belgium; died 3 Feb 1399, Castle, Leicester, Leicestershire, England; was buried 15 Mar 1399, St Paul's Cathed, London, Middlesex, England. [Group Sheet]

1. Lancaster, Catherine was born Bef 31 Mar 1373, Prob, Hertford, Hertfordshire, England; died 2 Jun 1418.
2. Lancaster, John was born Abt 1374, of, Hertford, Hertfordshire, England.