> ... The musical theme was the "Battle of Waterloo". ...  As was
> reported, the composition was initially written as a sort of parody
> of the 1812 overture so that places the date of writing perhaps in
> the late 1800's.

Battle pieces go back at least as far as the renaissance, but they
were particularly popular in the 19th century.  Your logic of placing
"Battle of Waterloo" in the "late 1800s" doesn't follow.  Anytime after
1812 would be possible.

"Battle of Waterloo" was extremely popular and was reprinted often
during the 19th century.  I believe it was composed around 1818
(if my memory serves me right) by an otherwise unknown Scottish
composer named Ogilvy (or something close to that).

Your description of it being played by two opposing orchestras is
interesting, something I haven't come across before.  Battle pieces
were commonly played on piano.  Thoreau derided the performances he had
heard of "Battle of Prague" (Koczara), probably the most popular battle
piece in 19th century America.  Another very popular battle pieces in
were "Battle of New Orleans."  One of the noted compositions of "Blind
Tom" was "Battle of Manassas."

As a resident of Long Island, I was pleased when I found the sheet
music for "Battle of Long Island," but it is tame, unimaginative,
and totally lacking in fire.

Ed Berlin