How do we distinguish between Classical and Romantic?

[rosflute]

And the simpler answer: brass and w'wind instruments had not yet been built in 1796 with the capacity to play what is written in Mahler 3. One of the flute players in the premiere of Parsifal had to change his instrument to a newer one because Wagner did not like the sound of the new, but not new enough, cylinder flutes. Flutes in 1796 couldn't play top C and did not have the dynamic colouring for a Mahler symphony. Brass instruments were 'natural'instruments ......

[TerraEpon]

I think above answers are mostly really missing the fundamental points of the answer. What text it uses is irrelevant. What instruments Mahler chose and what they could play is mostly irrelevant.

The question isn't "why couldn't it have been written' but rather, "why couldn't music /in its soundworld/ be written".
To put it a different way, Prokofiev's 1st uses a classical orchestra and AFAIK even instruments of 1796 could have PLAYED the symphony (I'll grant I haven't studied it and maybe I'm wrong).
This was touched on by eschiss but I think the main issue is very simple -- the melodic and harmonic make up of the work would have sounded so extremely WRONG to the composers of the era they never would have fathomed putting together music in that way. It's hard to really fathom such thoughts with how music is in our day, having been exposed to pretty much everything. But then? It just was beyond their reasoning to even think that way.

[Alan Howe]

I don't think the two previous posts are incompatible. After all, certain sounds couldn't even be imagined unless the instruments that make them were in existence - and, vice versa, the development of certain instruments itself prompted the composition of music that simply couldn't have been written before.

[rosflute]

TerraUpon have you looked at the score of the Classical symphony? I don't think that Top D in the flute part [to name but one thing] could have featured in earlier symphonies!

[TerraEpon]

As I said, I haven't studied it. But again, the instrumental ranges aren't really that relevant over all. A few impossible notes here and there being changed wouldn't radically change anything about the essence of how it sounds.

[eschiss1]

That's not true, I think, or not really quite. The instrumental changes - increases in compass being one of them - in the 19th century especially - were individually some of them less important than others (but: consider the difference between being able to write for valved horn vs. natural horn- etc. Mahler includes a posthorn solo in his 3rd symphony- and it's worth asking why people speak of his fourth symphony as something of a "classical" outing itself (I don't agree, except in very loose and relative terms, but it is worth talking about, again.) But instrumental changes speaking generally --- there're reasons why the internal balances of a Beethoven or Mozart symphony (or other work from that period, of course...) played in a modern hall by a modern-sized orchestra using modern instruments are going to not come off, often enough, I gather, and the fault does not (always) lie with the composers. (Forsyth wrote about this as early as the early 20th century in his orchestration book...)

And while the author of the text is irrelevant to us here in this connection for this etc., a major divider between the Classical and Romantic eras in music was their connection between the Classical and Romantic eras in the arts generally- the greatly increasing connection, for instance, of music with other arts. (Iirc probably not until Mahler's _6th_ symphony do you have one of his symphonies where an imaginary knowledgeable contemporary critic couldn't point to -some- such connection, if only a Wunderhorn-lieder connection at least, but often more explicit ones- Klopstock, Nietzsche... etc.)

[rosflute]

 "A few impossible notes here and there being changed wouldn't radically change anything about the essence of how it sounds."

So the opening notes of the Rite of Spring would be OK played an octave lower on the bassoon, would they? Stravinsky deliberately wrote a note that was alsmost impossible to play [in 1910] because he wanted that raw, untutored sound. That concentration on the textural quality of the music is one of the hallmarks of the Romantic period and on. A few notes played an octave lower in the Classical symphony would radically alter the sound of it.

[TerraEpon]

Ugh. Never mind. if you don't want to read what UI'm saying then I won't waste my time./

[semloh]

I think the discussion has veered away from the difference between classical and romantic (music). 

The issue is not why a particular style of music (romantic) couldn't have appeared at another point in time (classical); rather, it's about how we distinguish between the two. Instrumentation sometimes plays a part, along with a host of technical developments not previously available, and these often contribute to the kind of differences of which we, as listeners, are aware.

I wonder if the intentions of romantic composers are significantly different from those of classical composers. Perhaps that's another factor worth thinking about.

[chill319]

I'm learning a lot from this discussion. What fun!

And I take semloh's point about intentions, though, speaking generally, that may be too slippery a fish to plan a meal around.

To me the launching pad for the romantic period is Goethe's epochal Die Leiden des jungen Werthers. I would love to know what Goethe's intentions were in writing it. (And that may be well documented. I know little about Goethe.) Even so, it's generally accepted, is it not?, that Sturm und Drang was, at least in part, propelled by this work's effect on German-speaking culture.

So here's my take. Please correct me if you think I'm off base or oversimplifying -- and please forgive me if I seem diffuse (I'm packing a lot of rumination into a short span).

Without knowing anything biographical about Goethe's intention/s, we know that Werther's narrative is driven less by, say, Aristotle's Poetics than by personally discovered psychology.  Haydn's Sturm und Drang symphonies (for instance) and some of Mozart's and many of Dussek's keyboard sonatas (for instance) find an intensity of expression that relates first and foremost to gesture shaped by psychology. Yet the bottle into which the wine is poured is still a bit predictable, shape-wise, isn't it? Yes, Mozart wrote some Italian-style sonatas that begin recapitulation in the subdominant. But, such relative trivialities aside, such works still conformed to an evolving best-practice sonata form idea that was prevalent in the 1760s, 1770s and 1780s. And so did virtually all Sturm und Drang symphonies, don't you think?

It's fair, perhaps, to ask: When did the narrative example of Werther spread in music from (a) simple intensity of gesture ("expression") within more or less predicable form to (b) the motivation for a unique (psychological) narrative strategy? This didn't happen all at once, of course. A breakthrough in that direction is the long elaboration on a single harmony in a harmonic progression, which turns a formal signpost into a narrative event. (Dussek may have invented this in response to his experience of the French Revolution, but today we associate it especially with Beethoven). Whoever the first players were,  it was an evolutionary case in point from a best-practice form to an unpredictable narrative form. And perhaps a clue as to where the dividing line lies between classic and romantic.

[eschiss1]

Erm. I still think we're putting too much emphasis on instrumental music in the Classical era, which would have befuddled many Classical composers who were, to the best of my limited knowledge, as much more concerned with opera and vocal music- Mozart sometimes, I gather, limited some of his major/substantial instrumental composition to the Lenten period and similar periods when opera was simply not allowed (or when he could not get an operatic commission...), or am I misremembering something? - almost to the extent inversely that the symphony/quartet/...'s specific gravity/importance/dignity crowds out that of opera in our classical-music consciousness now...

And a major change in opera, I think Alfred Einstein held (I may be mistaken that he held this, and he may have been mistaken even if he did claim this), was Mozart's replacement of what were in a way basically cookie-cutter undercharacterized, even interchangeable, commedia dell'arte types, with much more characterized and characterful figures, individualized by libretto (thanks to Beaumarchais-by-way-of-da Ponte) and by music, that one begins to find in his Marriage of Figaro. (And while the form is still that of a numbers opera (like the outward form of many a Romantic-era opera), the content- for quite a few reasons, but that reason was what your post put me in mind of; but certainly for many reasons - has much that is very new...)