Jean Metzinger see the cubist works in Room 7 and 8. While Pablo Picasso and Georges Braque are generally acknowledged as the founders of the twentieth-century movement that became known as Cubism, it was Jean Metzinger, together with Albert Gleizes, that created the first major treatise on the new art-form, "Du "Cubisme"", in preparation for the Salon de la Section d'Or held in October 1912. "Du "Cubisme"", published the same year by Eugène Figuière in Paris, represented the first theoretical interpretation, elucidation and justification of Cubism, and was endorsed by both Picasso and Braque. "Du "Cubisme"", which preceded Apollinaire's well known essays,
Constant Nieuwenhuys himself artistically and experimented with multiple techniques of art-making. He was inspired by Cubism, especially by Georges Braque. In 1946 his daughter Martha was born, followed by his daughter Olga in 1948. In 1946 Constant travelled to Paris for the first time where he met the young Danish painter Asger Jorn. The friendship between Jorn and Constant later formed the basis for the avant-garde movement CoBrA. July 1948 Constant founded Reflex "" with Corneille, Karel Appel and his brother Jan Nieuwenhuys. The first edition of the magazine "Reflex" was published with a manifesto written by Constant. For Constant art had