Classical Sonata

The Classical sonata is a multi-movement instrumental work — usually three or four movements — for a solo instrument (most often piano) or for a duo (violin and piano, cello and piano, etc.). The first movement is in sonata-allegro form: a two-theme exposition (typically first theme in the tonic, second theme in the dominant or relative major), a development that fragments and recombines the material in distant keys, and a recapitulation that restates both themes in the home key. Slow second movements are lyrical, often in song or variation form; minuet or scherzo third movements (in four-movement works) provide dance contrast; finales are typically rondos or further sonata-form. The form was the central vehicle of Classical-era instrumental thought.

The Classical sonata grew out of the Baroque keyboard sonata of Domenico Scarlatti and C.P.E. Bach. Haydn's sixty-plus keyboard sonatas defined the early Classical version; Mozart's eighteen piano sonatas and a similar number of violin sonatas brought operatic lyricism to the form. Beethoven's thirty-two piano sonatas (1795-1822) are the genre's central monument — they extend the formal scheme through the entire Romantic possibility space, from the early three-movement works through the architectural late sonatas (Op. 106 'Hammerklavier,' Op. 110, Op. 111). Schubert, Brahms, Liszt and twentieth-century composers (Prokofiev, Scriabin, Boulez) continued to write sonatas, but the Classical-era examples remain the form's reference points.

Track the two contrasting themes in the exposition — the first usually decisive, the second usually lyrical — then listen for how they get cut up, modulated and recombined in the development. The recapitulation should feel like a return home; the keys realign and both themes appear in the tonic. Listen too for what Beethoven did to the slow movement: from the 'Pathétique' (Op. 13, 1798) onward, the slow movement carries the work's emotional weight as much as the opening.

Beethoven's Piano Sonata No. 14 in C-sharp minor, Op. 27 No. 2 ('Moonlight,' 1801), is the most-played entry — and its first movement is a deliberate departure from sonata-form, a clue that Beethoven was already remaking the genre. For pure Classical sonata-form, Mozart's Piano Sonata No. 11 in A major, K. 331 (c. 1783), or Haydn's Sonata in E-flat, Hob. XVI:52 (1794).

Beethoven's final piano sonata, Op. 111 (1822), ends with a long arietta variations movement whose late passages anticipate ragtime syncopation by nearly a century — modern listeners often hear what sounds like swing in it. The composer wrote no further piano sonatas in the remaining five years of his life.