Beethoven’s so-called "heroic” style, in full bloom in the Third ("Eroica”) Symphony, was not born overnight.  Almost every one of Beethoven’s early works has something in it that anticipates the explosion of the "Eroica” and the compositions that followed it.  

In his First Symphony (1799-1800), Beethoven basically followed the outlines of a late Haydn symphony, though signs of a new musical world taking shape were numerous.  In the Second Symphony, the occasional echoes of Haydn and Mozart are secondary in a symphonic style that was moving on an entirely new plane.

Soon after the first fortissimo D that begins the symphony’s opening "Adagio molto,” it becomes clear that we are listening to no ordinary symphonic introduction.  The first great change is in the orchestration:  the opening melody of the "Adagio” is given to the woodwinds while the strings are silent—it is the first indication that the winds will have much more to do in this symphony than merely doubling the strings and taking a solo or two.  When the woodwind melody is repeated and expanded by the strings, we know that the equal balance between these orchestral sections was a primary concern of the composer’s.

There are other novelties.  The music starts out on a series of modulations to distant tonalities; the strings scurry up and down in passages and rapid thirty-second notes into which the horns interject some strong off-beat accents.  One can recognize Mozart’s "Prague” Symphony (in the same key of D major) as a model, but Beethoven packed a far greater number of events into little more than two minutes of music.

The same intensity continues in the ensuing "Allegro con brio.”  The first theme (its simplicity and the repeated D’s again recall the "Prague”) starts piano, but it is not long before a full orchestral forte is reached.  The woodwinds and strings take turns as they play the second theme, a brilliant march suddenly interrupted by a fortissimo dissonance and, after it, a sudden silence.  The same elements are elaborated upon in a varied and exciting development.  The recapitulation is followed by one of Beethoven’s first grand codas, expanded almost to a second development section.

Whereas the first movement emphasized rhythmic action, the exquisite second-movement "Larghetto” is all melody and lyricism.  The themes, again arranged in sonata form, unfold with a grace and elegance that was new in Beethoven’s music.  This is a side of Beethoven’s style that found continuation in Schubert.  Despite occasional turbulences, the movement preserves its serene and peaceful quality to the end.

The third movement is Beethoven’s first orchestral "Scherzo” that is so labeled in the score.  (The corresponding movement in the First Symphony, although scherzo-like in many respects, was still called a Minuet.)  In the 1790s, Beethoven had written numerous scherzos, so designated, in his piano sonatas and chamber works; but in the Second Symphony he took the concept further than he had ever done before.  The humorous nature of the movement is accentuated by the reduction of the thematic material to a single measure, its three rapid quarter-notes constantly played at various pitches and different dynamic levels—and always differently from what one would expect.  In contrast, the Trio has a continuous melody, although again a disarmingly simple one, consisting merely of parts of an ascending and descending D-major scale.  Beethoven was to come back to these D-major scale patterns later, fashioning the Trios of both his Seventh and Ninth Symphonies from the same material.

The finale starts with another Beethovenian joke, a two-note motif played in a high register and answered by a "growl” an octave and a half lower.  The entire movement is energized by the sparkling wit of this opening.  Between the appearances of the two-note motif and its complement, there are some more expansive lyrical melodies.  In the final measures of the symphony, Beethoven derives a brilliant coda from this returning motif, and a whole magnificent and powerful conclusion grows out of that humorous little phrase.