Cassation Redux?

In my Examiner.com piece yesterday about the Tone Poems volume of The Sibelius Edition, I took issue with Andrew Barnett's observation in the accompanying booklet that Jean Sibelius' Opus 6 "Cassazione" "certainly merits a place among the tone poems." Through my own listening experiences, I have tended to associate the terms "cassation" with Wolfgang Amadeus Mozart and Joseph Haydn, both of whom seemed to use it synonymously with "divertimento" and "serenade." This afternoon I decided to consult Grove Music Online to sanity check my memory. The entry, by Hubert Unverricht and Cliff Eisen, makes a rather curious distinction between the "soloistic cassation" (which, presumably may involve more than one solo instrument) and an "orchestral" version. It associates "divertimento" with the first and "serenade" with the second. I am not sure quite how to interpret this, let alone if I agree with it; but it was nice to see that my memory was basically on the right track.

The article concludes by stating that the term had "fallen into disuse" by the time of "Beethoven's youth" (a rather interesting way to fix a span of time in history). It then cites the Sibelius Opus 6 as a "rare modern example." There is certainly no confusing that music with Mozart's K. 99 in B-flat major (the specific example I cited in my Examiner.com piece). Sibelius was certainly not trying to use Mozart (or Haydn) as a model in his own cassation. Having listened to the piece several times, I would now hypothesize that he knew full well that this nomenclature was covered in cobwebs; and he decided to give it a good shaking in the fresh Finnish air. That last phrase captures much of the spirit in this relatively short work of four movements performed without interruption. If this was nothing more than an attempt to air out a distant past, then it certainly yielded refreshing results!