According to Stravinsky, Petrushka started out as 'an orchestral work with the piano playing the most important part – a kind of konzertstück.’ It was the impresario Serge Diaghilev, founder of the Ballets Russes, who persuaded him to transform this existing material into a full-length orchestral ballet score. Stravinsky almost invariably composed sat at the piano – the shape of his ideas was determined by the instrument’s essentially percussive nature. In the case of Petrushka, the title character’s distinctive harmonic profile rose directly from the juxtaposition of two chords based respectively on the keyboard’s white and black notes. The piano-duo version is therefore no mere arrangement but the original source out of which the orchestral score was fashioned.