The 9th violin sonata, also referred to as KV 14 and the 5th piece in opus No.3 can be performed on the flute with the optional addition of a violoncello to support the piano bass. It is the 5th sonata in the series of Mozart's six violin-piano sonata dedications to Queen of the United Kingdom, Sophie/Sophia Charlotte of Great Britain. Mozart had written the compilation while in London for a year, during his tour of Europe. The early sonatas are often accompanied by Harpsichord in performance, instead of piano.