Most people argue that because Beethoven kept pushing the boundaries further and further on sonata form and dissonance that he started the Romantic Revolution. On the other hand, I have heard a few people say "Beethoven is only really part of what brought the Romantic Revolution. Had it not been for Schubert and Chopin, we wouldn't have had the Romantic Period as we know it."
But if I'm not mistaken, I hear a tiny bit of romanticism in Mozart's late works, especially works like Symphony no. 40. Repeated dissonant chords just to name one aspect of it. So like I hear a progression towards Beethoven as I go from early Mozart works which sound very Haydnesque, to late Mozart works which start pushing the boundaries. Albeit, very few if any diminished 7ths unlike Beethoven but who is to say that Beethoven really started the Romantic Revolution when you can clearly hear a bit of it in late Mozart? Who isn't to say that if Mozart had lived 20 years longer, there would be no need for Beethoven in the Romantic Revolution?
So I think Mozart is really the composer who started the Romantic Revolution. And some sources say the Romantic Period started in 1770 which would match up with Mozart starting the Romantic Revolution. Most though put the start of the Romantic Period at 1800, the year that Beethoven premiered his first symphony which matches up with the majority who say that Beethoven started the Romantic Revolution. I have even seen a few sources go as far as 1815 for the start of the Romantic Period. That would make Symphony no 9, Beethoven's only Romantic period symphony.
That certainly doesn't sound right to me. I would put an upper boundary on the Classical period of at the latest 1808, the year Symphony no 5 was premiered. Symphony no 5 sounds way too revolutionary to me to be considered to be from the Classical period. I mean, a whole symphony based on just 1 four note motif? A second movement in the key of the submediant? That is certainly unusual for the time that Beethoven composed his 5th symphony. Most minor key symphonies at the time would have a second movement in one of 3 keys:
- Dominant minor/major
- Subdominant minor
- Relative major
The parallel major fourth movement is not nearly as unusual though. It is like the symphonic version of the Picardy Third.
So did Beethoven really start the Romantic Period if there is already romanticism in late Mozart, 3 decades before according to most sources, the Romantic Period started?