Exploration of Beethoven’s Early Harmonic Language: Taking the First Movement of Piano Sonata in C-sharp Minor as an Example

Beethoven's "Piano Sonata in C-sharp minor" (also known as "Moonlight Sonata") is a very famous piano masterpiece in the world, and it is also a typical example of his early exploration of harmonic language style, which can enable analysts to find a lot of information from it. The use of Naples chords, various relative major & minor, Parallel major and minor – with the same tonic, and the use of diminished seventh chords for modulation, are all evidence of Beethoven's desire to seek breakthroughs and innovations in harmonic language. However, his early style was basically a continuation of harmony in classical music, but it already showed his own unique personality.