The theme of the Haydn Variations is really not by Haydn at all, although Brahms thought all his life that it was. Brahms found the melody in an 18th-century Feldparthie (wind octet) whose manuscript had been discovered by his musicologist friend, Carl Ferdinand Pohl, the author of the first scholarly biography of Haydn. Pohl attributed this octet to Haydn, though modern research ascribes it to Haydn’s student Ignaz Pleyel. In any case, the melody itself is neither Haydn nor Pleyel but a traditional chorale that used to be sung in village processions on the feast of St. Anthony of Padua.
Brahms was a supreme master of the variation form, which he used frequently both in movements from longer works and in self-contained compositions. The possibilities open in a Brahms variation set go well beyond ornamentation or changes in tempo, meter or key. The chorale can become a passionate song, a light-hearted game or a graceful pastorale, as the basic melody gives rise to a whole series of new melodies. These share their underlying structure with the original theme, but each new melody is an independent entity, with a soul of its own.
The most remarkable feature of the %u201CSt. Anthony” theme is that it consists of two phrases of five measures each, not four as usual in Classical music. This peculiarity is carefully maintained throughout the eight variations, which otherwise explore a wide gamut of tempos, characters, compositional techniques, and – in the symphonic version – orchestral colours. (Brahms also wrote an alternative version of the Haydn Variations for two pianos.)
When stating the theme, Brahms stayed close to the original wind scoring of the Feldparthie. The theme has a definite archaic flavour to it, but as soon as the first variation starts, we are transported into unmistakably Brahmsian realms. The most striking traits of the composer’s style include his fondness for juxtaposing duple and triple divisions of the beat either simultaneously or in close succession, and his predilection for intervals of thirds superimposed one upon another. We find both of these fingerprints already in the first variation.
Brahms ended his variations with a passacaglia, that is, a set of variations within a variation. (He was to return to this form in the last movement of the Fourth Symphony.) The theme is transformed into a bass line that is repeated numerous times without change, providing a stable %u201Cground” against which ever-changing counter-melodies are played. These mini-variations are arranged in a continuous movement whose progression is unbroken and completely seamless. The work closes with the original form of the St. Anthony chorale returning triumphantly in a full fortissimo.