The Sonata in E-flat major No. 49 is one of Haydn's most popular piano sonatas ever. He dedicated it to Anna Jerlischek, in charge of the Esterházy household, who had commissioned it. However, Haydn had apparently been working on the work for some time when he received this commission and originally had another dedicatee in mind, Maria Anna von Genzinger, the wife of the Viennese personal physician of Nicholas I Esterházy. In the P.S. of a letter to her, he wrote: "N.B.: Mademoiselle Nanette [An...