Listen to Fantasie on a Theme of Schubert in A-Flat Major, Op. 21: Theme online. Fantasie on a Theme of Schubert in A-Flat Major, Op. 21: Theme is an English language song and is sung by Rachel Brown. Fantasie on a Theme of Schubert in A-Flat Major, Op. 21: Theme, from the album Rachel Brown Performs Schubert & Boehm, was released in the year 2013. The duration of the song is 1:06. Download English songs online from JioSaavn.