Essentially, Felix Mendelssohn-Bartholdy (1809-1847) summarised three preludes and fugues as op. 37: in C minor, G major and D minor. They were composed during the last phase of his life and are also a reminiscence by Mendelssohn-Bartholdy of Bach’s fugues. The fugue in C minor, composed in 12/8 time, is perhaps the one for which Mendelssohn-Bartholdy improvised the most while writing. For their ‘The Mendelssohn Project’, cellist Emily Wittbrodt and organist Annie Bloch have taken on this C minor fugue. In order to make it the basis for their improvisational process, they first analysed Mendelssohn-Bartholdy’s compositional principles before performing his C minor fugue as improvisation artists of today and being able to shape it in a new and different way as a recomposition. For Wittbrodt and Bloch, it is true that a piece of written music is nothing other than coagulated improvisation, just as improvised music is a piece of volatilised composition.