Ludwig van Beethoven's Symphony No. 10 in E♭ major is a hypothetical work, assembled in 1988 by Barry Cooper from Beethoven's fragmentary sketches for the first movement. All the sketches assembled were clearly intended for the same symphony, which would have followed the Ninth, since they appear together in several small groups, and there is consensus that Beethoven did intend to compose another symphony. Cooper's score was first performed at a concert given in 1988 by the Royal Philharmonic Society, London, to whom Beethoven himself had offered the new symphony in 1827. The score is published by Universal Edition, Vienna, and appeared in a new edition in 2013. In 2019, artificial intelligence was used to reconstruct the third "Scherzo, Allegro" and fourth "Rondo" movements of the symphony, which premiered on 9 October 2021, titled Beethoven X: The AI Project. Background After completing the Ninth Symphony in 1824, Beethoven devoted his energies largely to composing his late string quartets, although there are contemporary references to some work on a symphony (e.g. in his letter of 18 March 1827); allegedly he played a movement of this piece on the piano for his friend Karl Holz, whose description of what he heard matches the sketches identified by Cooper. Cooper claimed that he found over 250 bars of sketches for the first movement, which he wove together to form the movement, keeping as close as he could to Beethoven's style and sketching processes. Cooper's movement consists of an Andante in E major enclosing a central Allegro in C minor. Cooper claimed to have also found sketches for a Scherzo and other later movements, but he deemed them not extensive or developed enough to be assembled into a performing version. There are a few references to this work in Beethoven's correspondence. (He had originally planned the Ninth Symphony to be entirely instrumental, the Ode to Joy to be a separate cantata, and the Tenth Symphony to conclude with a different vocal work.) Earlier, in 1814–15, Beethoven also began sketches for a 6th piano concerto in D major, Hess 15. (Unlike the fragmentary symphony, the first movement of this concerto was partly written out in full score and a reconstruction by Nicholas Cook has been performed and recorded.) Recordings Two recordings of Cooper's reconstruction of the first movement of the "Symphony No. 10" were released in 1988, one conducted by Wyn Morris and the other by