What are the two themes of the classical sonata form?

The two themes in classical sonata form are typically referred to as the "first theme" and the "second theme." The first theme is usually presented in the home key and establishes the main musical material, while the second theme often contrasts with the first, typically appearing in a different key and showcasing a contrasting character or mood. This structure helps create tension and resolution throughout the movement, leading to a development section where both themes are explored and transformed before a recapitulation brings them back to the home key.