J. Delville, 'Notice sur Fernand Khnopff', in Annuaire de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique, Brussels, 1925, p.28. ~R. L. Delevoy, C. de Croës and G. Ollinger-Zinque, Fernand Khnopff, Brussels, 1979, no.623 (reproductions illustrated pp.406-407).~~These drawings are studies for Fernand Khnopff's illustrations to Pelléas et Mélisande by Maurice Maeterlinck, a copy of which accompanies this lot. Originally performed in 1893, Maeterlinck's symbolist play in five acts tells the tragic story of two doomed lovers. Enthusiastically received, it was adapted as an opera in 1902 and set to music by Claude Debussy. Khnopff drew fifteen illustrations for the 1920 publication, including five main plates within the text, and ten smaller head- and tail-pieces above and below each act.~~Khnopff worked frequently with his compatriot Maeterlinck: the illustrations to Pelléas et Mélisande represent the fruits of 30 years of close collaboration. As Michel Draguet has noted of the hand-coloured illustrations to this de luxe 1920 edition, '...in fidelity to the world of Maeterlinck, Khnopff limited his palette to the demonic reds of the hair which envelops the body and is a prelude to the Ophélisation of the figure [Mélisande] and to blue and green to render the vegetal atmosphere of a liquifying universe. ... The architecture appears as rigid as destiny. The space is articulated with severity, a dialogue between black and white undoubtedly inspired by the work of [Charles] Doudelet.' (M. Draguet, Khnopff ou l'ambigou poétique, Brussels, 1995, pp.197-198).