In the development section of sonata form, what happens to the thematic material?

In the development section of sonata form, the thematic material is altered, modified, and transformed. This section is crucial for expanding and exploring the musical ideas introduced in the exposition. Composers take the themes and subject them to various manipulations, such as changing the key, reworking the rhythm, using different instrumentation, and mixing elements to create new textures. This transformation adds depth and complexity to the music, allowing for a greater emotional and dramatic range.

The focus on altering the themes in the development section serves to create tension and contrast, preparing the listener for the return of the themes in the recapitulation. By modifying the material, composers can develop new themes and motifs, thereby enriching the overall musical narrative.