John married Plantagenet, Joan Abt 1339. Joan (daughter of Plantagenet, Earl/Lancaster Henry and De Chaworth, Maud (Matilda)) was born Abt 1306, Grismond Castle, , Monmothshire, England; died 7 Jul 1349; was buried , High Alter At, Byland. [Group Sheet]

1. de Mowbray, Baron Mowbray John was born 25 Jun 1340, Epworth, Isle of Axholme, Lincolnshire, England; died 1368, Constantinople, Constantinople, Turkey.
2. de Mowbray, BaronessPoyning Blanche was born Abt 1341, of, Epworth, Isle of Axholme, Lincolnshire; died 21 Jul 1409.
3. Moubray, Bns/LaWarr Eleanor (Alianore) was born Abt 1342, of, Epworth, Isle of Axholme, Lincolnshire; died Bef 18 Jun 1387.