What classical could be considered prog?

[ivan_2068]

Night on Bald Mountain......Modest Petrovich Moussorgsky
Prince Igor......Alexander Borodin
Firebird Suite......Igor Stravinski

If any classical music should be considered Progressive is the Russian Nationalist Movement (Late Romantic/Early Modern) because:

1.- They broke with the mainstream that came from Europe.

2.- They refused to play popular music like Waltzes (There's an anecdote about the Mighty Handfull, who were forced to play in a public park during Russian winter because they refused to play Strauss in the Viena Court, even when they were offered very big bucks).

3.- They were considered extremely complex for their era.

4.- Almost all the world (Except Russia) hated their music during their life time.

5.- They gave extreme importance to the concept.

Does it sounds familiar?

Iván