Bach’s Toccata and Fugue in D minor, BWV 565, is arguably the most iconic piece ever written for the organ. But did Bach actually write ‘565’? If not, then who did? Was it written for the organ? Is it even a Toccata and Fugue?

In this extract from the Fugue State Film’s documentary The Great Toccata, presenter Dan Moult outlines the mysteries and questions behind the organ’s most famous piece.