All: Yes, John of Gaunt's first wife was Blanche. She was the inspiration for Chaucer's "Book of the Duchess." You "other" Nevilles descend from Katherine. She was one of Blanche's ladies-in-waiting and John's long time mistress. She seems to have had the good taste to wait until after Blanche's death [black plague] to take up with John. Chaucer's wife Phillipa was Katherine's sister. John of Gaunt m. 1. Blanche of Lancaster children: 1. Phillipa (1360-1415) m. Joao of Portugal 2. Elizabeth (1364-1426) m. 1. Earl of Pembroke 2. John Holland 3. Henry of Bolingbroke (1367-1413) m. Mary de Bohun Gaunt m. 2. Costanza of Castile children: 4. Catherine m. Enrique of Castile Gaunt m. 3. Katherine (de Roet) Swynford (1350-1403) (she m. 1. Hugh Swynford); she was the daughter of Sir Payn de Roet. children: 1. John Beaufort (1372-1409) m. Margaret Holland (parents of Henry VII) 2. Henry (1375-1447) - Cardinal Beaufort 3. Thomas Beaufort (1377-1427) m. ? 4. Joan Beaufort (1370-1440) m. 1. Sir Robert Ferrers 2. Ralph Nevill of Raby Katherine's children by Hugh Swynford 1. Blanchette (1367-?) 2. Thomas (1368-1432) m. 1. Jane Crophill 2. Margaret Darcy Kathy