The opening movement begins quietly with a march figure, but quickly moves to a more lyrical melody interspersed with a fanfare in the winds. The music grows abruptly in volume, with the violins taking up the principal melody over the march theme, which is now played by the brass. This uplifting theme transitions to a brief, quieter interlude distinguished by a sighing motif in the brass. The march returns, eventually transitioning to the entrance of the soloist. The soloist plays a brief Eingang (a type of abbreviated cadenza) before resolving to a trill on the dominant G while the strings play the march in C major. The piano then introduces new material in C major and begins transitioning to the dominant key of G major. Immediately after an orchestral cadence finally announces the arrival of the dominant, the music abruptly shifts to G minor in a passage that is reminiscent of the main theme of the Symphony No. 40 in that key. A series of rising and falling chromatic scales then transition the music to the true second theme of the piece, an ebullient G major theme, which can also be heard in Mozart's Third Horn Concerto. The usual development and recapitulation follow. There is a cadenza at the end of the movement, although Mozart's original has been lost.