Every once in a while I come across new information on a composer for whom I thought I knew everything there is to know.
Here is an example of that:
Beethoven did not actually write a 10th Symphony. He was working on some sketches for a 10th at the time of his untimely death.
In the 20th Century, those sketches were transcribed into what is described as a hypothetical work, Beethoven's 10th symphony. It doesn't have an Opus number, and it's not actually presented as Beethoven's work, but as the work of a musicologist and Beethoven scholar by the name of Barry Cooper (b. 1949).
Here is the first movement - in E flat major.
Beethoven started working on this symphony in 1825 before he completed the 9th symphony. The symphony as recorded does not have nearly the scope nor length of his later symphonies, but is interesting, and I think Cooper has done a fine job in imagining how Beethoven might have completed it. His work sounds true to Beethoven, and while others may disagree, I think he does justice to the composer, even though if Beethoven had completed it, it would probably be much different.
While there are a couple of other recordings, I found one available here.