Paul Klee was a Swiss born German painter and important figure in the development of early 20th century avant-garde art. Klee was originally associated with German Expressionist group Der Blaue Reiter, and eventually started teaching at the Bauhaus, a widely influential German art school. Klee’s breadth of subject matter ranged from the child-like portrait Senecio (1922), to the geometric abstraction of Castle and Sun (1928). He often painted architecture as well as the natural world, using his signature expressionist style to represent space.