Exposition, Development, and RecapitulationIn a sonata-allegro form, the source of the “drama” is the establishment of a “tonal conflict” in the first section, the Exposition, by virtue of a modulation from the original tonic key toa closely related key. In a major-key piece, the modulation is normally to the dominant key (V). In a minor-key piece, it is normally to the Mediant (III).Two different tonalities–often with contrasting themes–are now vying for supremacy. In a certain way, these conflicting tonalities create a large-scale “dissonance,” which means that a resolution will be necessary before the end of the movement. And, just in case we missed the establishment of the tonal conflict the first timearound, the Exposition of a Classical sonata-allegro form is customarily repeated.In the Development section that follows, the tonal conflict is intensified. Much like the digression that follows the double bar ina rounded binary form, the Development section of a sonata-allegro form is characterized by tonal instability. Fragments of themes from the Exposition are often heard, but the tonal ground keeps shifting. Phrase structures become irregular. Uncertainty reigns, as the tonal conflict intensifies.Finally, at the end of the Development section, we arrive at dominant harmony–the V chord–in the original key. In many sonata-allegro movements, this dominant harmony might be prolonged for several measures, sometimes longer, adding to the excitement, because it is preparing us for the inevitable final section: the Recapitulation.At the beginning of the Recapitulation, the original theme returns, triumphant. The tonic key will be affirmed unequivocally. Not only do we hear the original theme in the tonic key. But now, the other themes from the Exposition that we had previously heard in another key are “recapitulated” in the tonic key. This is the ultimate resolution of the tonal conflict established in the Exposition.