From the Publisher
In January 1824 Schubert himself called the work succinctly “Variations pour Pianoforte et Flûte". Judging from the first edition (“Introduction et Variations sur un thème original", published posthumously in 1850), it doesn't seem as if Schubert borrowed the variation theme from the song “Trockne Blumen" from his cycle “Die schöne Müllerin".
The addressee for both instruments was presumably the flutist Ferdinand Bogner, a friend of Schubert's. The work makes equal – and highly virtuoso – demands on the players. For their revision, the editors Nikolaus Delius and Paul Badura Skoda consulted the autograph, which is housed in Vienna's Stadtbibliothek.
Difficulty level, roughly compared to ABRSM exam grades. 0 is beginner, 9 is advanced (beyond grade 8).