The symphony emerged in the mid-18th century and was initially an almost entertaining genre. Symphonies were never played as the "main course", the key number in the programme. On the contrary, they were designed to "warm up" the audience before another, more ambitious work. Now this seems strange to us - after all, if you open the programme of any philharmonic society in the world, you will see that symphonies are performed at every second concert. And they are played not as warm-up music, but as the main "attraction" of the evening. Moreover, in contemporary programmes the symphonies are usually placed in the second movement of the concert, as the most substantial piece.
This difference tells us about the way the symphony had travelled from its birth until the first quarter of the 19th century, when the idea of it as a titular musical genre was established. This journey took more than half a century. One can see the difference particularly clearly if one compares different works by the same master. One can listen to Haydn's two symphonies - the early, 1760s, which still belongs to the world of pleasing secular pleasures, and the later, 1790s, when it builds up its power and scale.
The late classicist symphonies are written for a larger orchestra. The woodwind group expands (clarinets appear) and the brass group (now the brass group consists of trumpets, French horns and trombones). The form becomes more extended and extended. The symphony is still in four movements (fast - slow - dance - fast), but it can last up to an hour (as in Schubert's Symphony in C Major) or over an hour (as in Beethoven's Ninth).
The principal themes of the classical symphonies generally began with a compact, clearly delineated thesis - just as a literary story begins with the introduction of the protagonist. But in the early 19th century new variants of beginnings appeared - for example, languidly penetrating themes, as in Schubert's Unfinished Symphony, or gradually emerging from the rustle of themes-voices, as in the same Beethoven's Ninth.
The importance of rhythm became enormous: in the later Beethoven symphonies rhythmic figures begin to play the role of themes. What does this mean? Our ears are used to the fact that the most striking thing in music is the melody: for us remembering music means singing it out. But ever since the famous Fifth Symphony, which opens with a menacing 'knock at the door', Beethoven's short, haunting rhythmintonations attract more attention than the melodies they are superimposed on. We memorise the music and are drawn to it, drawn in by the beat and the pulse, rather than by the motif.
Finally, Beethoven's Ninth, already mentioned twice, which can be considered the last colossus of the Classical era, is a symphony whose finale is turned into a kind of civic prayer. Here a quartet of soloists (as in an oratorio) and a chorus (as in a mass) sing, while the second and third movements of the cycle swap places. Here, as we can see, the genre is reborn: the grandiose themes that occupied Beethoven (joy as a utopian paradise for mankind, the brotherhood of all on Earth, an appeal to a superintelligent Deity) could no longer fit into the old symphonic framework.
By the way: rhythmic intonation is a kind of "speaking" rhythm, a short rhythmic figure with which the listener has a vivid image. We can, for example, speak of the rhythmintonation of a waltz or a funeral march. Both of these genres can be recognised by their rhythm, a three-dozen, flying rhythm in one case, and a pacing rhythm in the other.
Franz Joseph Haydn, Ludwig van Beethoven, Franz Schubert