Playing through Beethoven's Sonata for Piano and Horn, Op. 17 (with natural horn, of course) my attention was drawn to the designation "moderato" for the first and last movements. But I reported last week that Alfred Einstein found that Beethoven did not use the term. A bit of research into the Beethovenhaus archives showed that he did, indeed, use the term!
Fascinating that it is in a piece for the highly vocal natural (i.e., valveless) horn.
Allowing the word to enable stretchings of the beat from time to time utterly transformed the sonata, not only making it easier to play, but making it deeper on every level and in every respect.
