Pierre de Montferrand de Lesparre

from Plantagenet Ancestry: A study in Colonial and Medieval Families, Second Edition:

Mary of Bedford. She married before 1435 Pierre de Montferrand (or Montferrant), Knt., seigneur of Lesparre (Gironde) and Carcans (Gironde) in Aquitaine, Soudan (governor) of La Trau (Gironde), Sénéschal of Guyenne, son and heir of Bertrand de Montferrand, seigneur of Lesparre (Gironde), Sénéschal of Guyenne, by Isabeau, lady of la Trau, Landras, Portets, and Uzeste, daughter of Arnaud-Bertrand de Préchac (or Preyssac), Knt., Soudan de la Trau. They had three sons: Thomas (seigneur of Aiguille), Bertrand (seigneur de Montbadon), and François (baron of Uzeste and Portets, soudan of La Trau), and one daughter, Mathilde. In July 1450, the king granted him the barony of Marennes in the duchy of Aquitaine and the bailliage and péage of Hastingues in compensation of the lands, etc. granted to Pierre on his marriage to Mary, the natural daughter of John, Duke of Bedford. He was granted the keep of the châtellinie and Castle of Dax in Oct. 1451. After the Battle of Castillon 24 July 1453, he refused to make his submission to the King of France. He was subsequently captured and beheaded at Poitiers in 1454. His widow, Mary, returned to England where Henry VI granted her an annuity of 25 in 1457. Edward IV granted her a £20 annuity in 1459 and made an additional £40 settlement per year in 1461 and again in 1462. Mary of Bedford, lady of Lesparre, was living in 1463. She was specifically called "daughter of oure uncle late duc de Bedford" by Henry VI.

Pierre de Montferrand was casualty after the Battle of Castillon. He was was married to Mary Plantagenet, illegitimate daughter of the John of Lancaster, 1st Duke of Bedford and a granddaughter of Henry IV of England. Refusing to pay homage to the French king, he was subsequently beheaded in Poitiers on 12 July 1453.

http://en.wikipedia.org/wiki/Battle_of_Castillon