Literature / Legends and Myths. The Four Sons of Aymon (de Montauban). Regnault kills Berthoulet, the nephew of Charles I, during a game of chess. Illumination, French, 15th century. From the prose treatment "Regnault de Montauban" in 4 volumes, volume 2. Ms. Arsenal 5073, series 15 v. Paris, Bibliothèque de l'Arsenal.