Beethoven, in common with his predecessors Haydn and Mozart, uses the Sonata form in the first movement of his first symphony. This was Beethoven’s first attempt at the symphonic form having composed chamber music and two piano concertos. Beethoven made the sonata form more expressive through his use of dynamics and more extreme key relations.
Beethoven started this piece with a slow introduction. It is not unknown but it’s not commonly used. It was not uncommon for slow introductions to start in a different key as the first chord was not tonic but a dominant 7th chord. This is then followed by the first four cadences and none of them is the tonic. We would normally expect to have the key established immediately, and so starting with a dissonant chord is unsettling for the listener. The main focus of the beginning of a sonata form is the establishment of tonic, although Beethoven is not willing to establish the tonic chord.
The exposition gives a strong sense of tonic with a solid C major chord at bar 13. The shape of the first subject with dominant and leading note to tonic helps further establish the key. There is also a use of tonic pedal at bar 33 which helps emphasize the key. This means that Beethoven eventually confirmed the tonic key of C major.
Beethoven uses rising sequences for the transition. This cause tension and excitement to build up rather than just a smooth modulation to the dominant.
The second subject which is in the dominant key has a more lyrical feel to it. This actually conforms to expectations. There is a rising broken chord patterns in strings at bar 53 which ties in with a similar pattern in first subject at bar 16. Such links were not so commonly used but are very characteristic of Beethoven’s writing.
In the codetta, Beethoven uses the first subject. This creates unity and the feeling of rounding off the exposition. He also uses loud