Proto-Cubism that Metzinger was the first to recognize explicitly and implicitly the significance of the use of "a free, mobile perspective", and the "mixing... of the successive and the simultaneous". He was the first to write of the fact that artists had abandoned traditional perspective and were now free to move around their subjects to paint them from various points in space, and at various moments in time. Metzinger's role at center of Cubism both as a painter and theorist prompted Guillaume Apollinaire to write of Picasso, Braque and Metzinger as the first three Cubist painters. Now well beyond the teachings
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