Brahms' works for piano open and close his career as a composer. In his earliest sets of variations, especially those of Op. 9, the melody is of primary importance, and Brahms clings to it while freely changing the harmony. His later studies of Beethoven, however, led to his transformation of the melody into something new, adhering to the theme's basic phrase structure and harmonic pattern. As had Bach in his "Goldberg" Variations and Beethoven in the "Diabelli" Variations, Brahms, in the Variations and Fugue on a Theme of Händel, Op. 24, constructed a sprawling masterwork based on a very simple idea. Brahms' intended his earlier variations, such as Opp. 9, 2,1 and 23, for private audiences, but composed the Händel Variations and the later Paganini Variations, Op. 35, with the concert hall in mind. Composed in 1861 and published in 1862 by Breitkopf & Härtel in Leipzig, the Handel Variations were first performed by Brahms in Hamburg on December 7, 1861. The set is also one of the works with which Brahms introduced himself to Vienna in a concert of November 29, 1862.
Brahms may have been attracted by the utter simplicity of Handel's theme and the challenge it posed. The melody is the Air from the third movement of the first suite in B flat major of Handel's Suites de pièces de clavecin of 1733. (Handel himself wrote a set of variations on this same Air.) Brahms certainly recognized the harmonic potential suggested by the theme's sequential structure, re-harmonizing recurrent notes. At several points, Brahms pairs the variations such that the second "varies" the material of the first. Donald Francis Tovey recognizes a larger grouping in variations 14-18, which he describes as "aris[ing] one out of the other in a wonderful decrescendo of tone and crescendo of Romantic beauty." Brahms did not at all abandon the past in his Handel Variations. A strict canon forms the basis of variation 6, and variations 5, 6 and 13 constitute the traditional ventures into the tonic minor. We hear a Hungarian rhapsody in No. 13 and a fast Siciliana in 12/8 in No. 19. Such distinct character is also to be found in the "music box" variation (No. 22) and the chromatic fantasia atmosphere of No. 20. The closing fugue, with a subject derived from the original Air, is a study in the free use of Baroque counterpoint.