This is Beethoven's Op.80, a work for piano, orchestra and chorus. It opens with a long introduction for piano solo. (The first time it was performed, Beethoven improvised the introduction, but later wrote it.) Then the orchestra gradually joins the piano, and near the end, the chorus joins the whole ensemble. Most of the second section is based on a set of variations on a melody, which reminds one of the famous main theme in his Ninth Symphony, written approximately fifteen years later.
