Beethoven's most famous piano student, the composer Carl Czerny, wrote in 1842 that the second movement of the Piano Trio in D, the Largo assai, reminded him of the ghost of Hamlet's father. He was close; evidence from pages of Beethoven's notebook suggests that the composer was discussing an opera of Shakespeare's Macbeth with the playwright Heinrich von Collin at the time. The words "Macbett" and "Ende" appear near sketches for the Largo. The "Ghost" movement was possibly meant for a scene of the three Witches. Czerny's nickname stuck; today the work is known as the "Ghost" Trio.

That middle movement is introduced with an eerie, sustained three notes in the strings, after which the piano responds mournfully. The strings and piano alternate this way through the introduction, thereby setting the ominous mood of the Largo. The dark D-minor melodies of the exposition become more forceful in its repeat. As the development begins, Beethoven modulates briefly to C major, then quickly moves on through several keys to re-establish the tense atmosphere. The end of the movement is characterized by gripping pauses and abrupt and intermittent stops and outbursts. With all its ghostly qualities, the movement's effects are achieved quite simply, with slow crescendos and diminuendos, chromaticism and silences, as well as impressionistic use of tremolando.

To set off the "Ghost" movement further, Beethoven made the outside movements shorter (each about six minutes long) and much more direct in style, giving the whole trio an arched shape. The first movement begins with a fast-moving rhythmic figure played in a vigorous unison; the main thematic material of the movement is played within the first several bars. The third movement, after the disturbance or even near-upheaval the listener has experienced in the center movement, is a return to more lucid writing, and serves as bright, warm relief. The music leaves out the sharp contrasts of both preceding movements, and instead flows serenely and seamlessly to the end.

Although Beethoven never actually abandoned the Classical harmonic language, the works of his second ("middle") period, including the "Ghost" Trio, gradually moved away from Classical models in terms of their length and intensity, as well as in their innovation. In addition, the music became increasingly difficult for even the top players of the time. The middle period, lasting roughly from 1802 to 1812, began as Beethoven was coming to grips with his emerging deafness during a six-month stay under doctor's orders in the village of Heiligenstadt, outside Vienna. The outcome of this was, of course, not a cure for his deafness but the composer's resolution of the crisis as laid out in the famous Heiligenstadt Testament. This letter, addressed to his two brothers, and found only after the composer's death, admits the extent of his hearing loss, and the resulting fear and shame Beethoven suffered. The music written during these years is notable, not surprisingly, for its expression of heroism and struggle, as well as its monumental scale. The Op. 70 Trios, written in Heiligenstadt in 1808, fall between the Fifth and Sixth symphonies and the Seventh and Eighth. As every one of those symphonies raised the bar, so scholar Lewis Lockwood says of the "Ghost" Trio: "(it) raises the genre to a level from which the later piano trio literature could move forward." By the end of Beethoven's second period, he was conceiving chamber music on an even more symphonic scale.

- Jessie Rothwell is the Publications Coordinator for the Los Angeles Philharmonic. She also writes music, plays the oboe, and sings Bulgarian folk music.