Serenade für Pianoflorte und Flöte in D major, Op. 41 by Ludwig van Beethoven: In 1803, Franz Xaver Kleinheinz arranged the serenade for flute (or violin) and piano. Beethoven checked and approved this arrangement and it was printed as his Op. 41. Similar to his Septet of the same period, the work had great popular appeal and was profitable for the young composer.