The richness of Wassily Kandinsky's life, work, and intellect make him one of the leading figures of twentieth-century art. He was a founding member of the artistic group Der Blaue Reiter (The Blue Rider), and his theories influenced many of the major artistic movements of his time, including Dada, the Bauhaus, De Stijl, and Russian Constructivism. A man of diverse interests, he was a friend to artists such as Marcel Duchamp and Paul Klee and had fruitful relationships with contemporary musicians including Arnold Schoenberg and Thomas de Hartmann.