How to finish a Mendelssohn sonata

Pianist David Louie on completing an unfinished composition

Violinist Benjamin Bowman (Credit: Bo Huang)

The ARC Ensemble recently recorded a new version of a previously incomplete Mendelssohn sonata, reconstructed from fragments by Canadian pianist David Louie. Here, Louie takes us through the process of reconstructing a work by one of our greatest composers.


In early 2010, the ARC Ensemble's artistic director, Simon Wynberg, invited me to look at an unfinished work by Felix Mendelssohn. The piece was to feature in the ensemble’s Music in Exile series, included in a programme that examined National Socialism's aversion to the composer, and the dispersal of his works during the regime's control. Scored for piano and violin, this undated, single-movement 'Sonata' is part of the Mendelssohn-Archiv in the Berlin State Library (MWV Q 18). It is thought that the piece was composed in 1825-26, when Mendelssohn was 15 or 16 years old, and it consists of 366 bars of unbroken content. So its performance is possible, although it lacks a conclusion, sputtering out with the iconic rhythmic motif that begins Beethoven’s Fifth Symphony, here stated pianissimo.

Mendelssohn’s fragment has promising musical potential and contains several striking melodic and harmonic ideas. It is possible to append an ending, as we did in our first performance, but it still lacks a cohesive sonata-form structure (its title notwithstanding) and the writing, particularly for the violin, is occasionally sketchy or incomplete; deficiencies uncharacteristic of Mendelssohn’s finished works, with their sophisticated craftsmanship and mastery of classical architecture.

A year after my introduction to the piece I decided to undertake a complete reconstruction. I cut the fragment into smaller parts, and (using the technique of collage) organized them so they constituted a classical sonata movement. I wanted to avoid the introduction of a foreign compositional style so I preserved, in some form or another, all of the material contained in the fragment, including large sections in their entirety. The resulting lacunae (gaps) were filled with newly composed material that expands on Mendelssohn's thematic ideas. Figurations that could amplify the texture were culled from other works by the composer, including the Double Concerto for Piano and Violin. In the recapitulation of my reconstruction, listeners may recognise the melodic peroration of the second theme as a borrowing from Mendelssohn’s E minor Violin Concerto.

Since 2011, Benjamin Bowman and I have performed my reconstruction of the Mendelssohn Violin Sonata in D minor (a fragment no longer) a number of times in ARC Ensemble concerts, notably at the Concertgebouw and Wigmore Hall. These live concert performances have helped to further refine the work and its reception has been both illuminating and rewarding. The recording, produced by David Frost is the culmination of this process.

Mendelssohn must have had ample reason to set aside this sonata and leave it unfinished. Perhaps his attention was diverted by one of a myriad other musical projects that date from the same time – songs, the Third Piano Quartet, the String Octet? Or perhaps he was slightly embarrassed by how much his idolisation of Beethoven had influenced this particular effort, especially since Beethoven was the most famous composer of the day. Today Beethoven’s influence on Mendelssohn’s prodigious and precocious talent can be unashamedly acknowledged, an influence that I have played up in my reconstruction of this sonata.

David Louie


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