http://www.kennedy-center.org/calendar/?fuseaction=composition&composition_id=2274:
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"The period in which Brahms began sketching this work was a very difficult time for him and his friends Robert and Clara Schumann. Robert had been confined in a mental asylum; Brahms did his best to provide moral support for Clara and her children, but his own emotions were extremely strained. In a letter to a friend at the time, in fact, he described the first movement of this work as a sort of musical corollary to the suicidal desperation of Goethe's Werther. Brahms did not share that remark with Clara, however, who found the movement simply underactivated. That could not be said of the scherzo that follows, which is almost brutal in its forceful drive. Respite comes in the Andante, which Brahms in his maturity (he had established his credentials in choral music with the German Requiem, and in the orchestral realm with the Haydn Variations by the time this work was completed) graced with an altogether characteristic lyric episode for the cello. By way of inevitable summing-up, the concluding Allegro, which begins with a provocative motif given the violin, with the piano emphasizing an atmosphere of general restlessness, and ends with a return the dark scenery of the work's opening—not in the form of any specific citation or reprise, but rather in the way of a general acknowledgement of the work's basic impulse."
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