Belief in a Germanic spirit—defined as mystical, rural, moral, bearing ancient wisdom, noble in the face of a tragic destiny—existed long before the rise of the Nazis; Richard Wagner celebrated such ideas in his work. Beginning before World War I the well-known German architect and painter Paul Schultze-Naumburg's influential writings, which invoked racial theories in condemning modern art and architecture, supplied much of the basis for Adolf Hitler's belief that classical Greece and the Middle Ages were the true sources of Aryan art.