Cubism Kahnweiler considers Cubism as Picasso and Braque," wrote Daniel Robbins, "our only fault is in subjecting other Cubists' works to the rigors of that limited definition." The traditional interpretation of "Cubism", formulated "post facto" as a means of understanding the works of Braque and Picasso, has affected our appreciation of other twentieth-century artists. It is difficult to apply to painters such as Jean Metzinger, Albert Gleizes, Robert Delaunay and Henri Le Fauconnier, whose fundamental differences from traditional Cubism compelled Kahnweiler to question whether to call them Cubists at all. According to Daniel Robbins, "To suggest that merely because these artists
20th-century Western painting for that spiritual knowledge. Other major pioneers of early abstraction include Swedish painter Hilma af Klint, Russian painter Kazimir Malevich, and Swiss painter Paul Klee. Robert Delaunay was a French artist who is associated with Orphism, (reminiscent of a link between pure abstraction and cubism). His later works were more abstract, reminiscent of Paul Klee. His key contributions to abstract painting refer to his bold use of color, and a clear love of experimentation of both depth and tone. At the invitation of Kandinsky, Delaunay and his wife the artist Sonia Delaunay, joined The Blue Rider (Der Blaue Reiter), a