GENYLON-OLYVER, or Oliver who is like Ganelon, refers to Olivier de Mauny, nephew of Bertrand du Guesclin, the constable of France. Both de Mauny and du Guesclin were sent by the French king to support Henry the Bastard in the Castilian civil war. After Don Pedro's murder in 1369 Henry established himself on the throne of Castile and gave Olivier de Mauny the estate of Crecte, worth two thousand florins a year. Froissart says that without the help of de Mauny and du Guesclin, Henry would never have won the throne of Castile (Chronicles I.245).

The Monk describes de Mauny as Genylon-Olyver, MkT 2389. Froissart does not mention treachery; Olivier was always on Henry's side throughout the war. [Charles Olyver: Genelloun: Petro¹]