On 23 August 1841 Chopin wrote to the Viennese publisher Mechetti: “I currently have a manuscript available for you. It is a kind of fantasia in the form of a polonaise that I would call Polonaise”. Chopin’s uncertainty about the title is only too understandable. The work begins as a proud polonaise.

Then a passage bursts in during which an octave a is relentlessly played more than thirty times. This almost modern sounding passage leads into a mazurka that seems to come from a different, enra...