[1] The singer takes the role of four characters — the narrator, a father, his small son, and the titular "Erlking", a supernatural creature who pursues the boy — each of whom exhibit different tessitura, harmonic and rhythmic characteristics.

A technically challenging piece for both performers and accompanists, "Erlkönig" has been popular and acclaimed since its premiere in 1821, and has been described as one of the "commanding compositions of the century".

The public premiere on 7 March 1821 at the Theater am Kärntnertor was a great success, and quickly propelled the young composer to fame in Vienna.

[7] Its form is the through-composed song; although the melodic motives recur, the harmonic structure is constantly changing and the piece modulates within the four characters.

The Erlking's vocal line, in the major mode, provides the only break from the ostinato bass triplets in the accompaniment until the boy's death.

A fifth character, the horse on which the father and boy are riding, is implied in rapid triplet figures played by the pianist throughout the work, mimicking hoof beats.

[10] The moto perpetuo triplets continue throughout the entire song except for the final three bars and mostly comprise the uninterrupted repeated chords or octaves in the right hand that were established at the opening.

In the introduction, the left hand of the piano part introduces an ominous bass motif composed of rising scale in triplets and a falling arpeggio, pointing to the background of the scene and suggesting the urgency of the father's mission.

After a long introduction of fifteen measures, the narrator raises the question "Wer reitet so spät durch Nacht und Wind?"

The father's question to his son is harmonically supported by a modulation from the tonic to the subdominant, also employing the "passing note motif" from the introduction.

After a short piano interlude, the Erlking starts to address the boy in a charming, flattering melody in B♭ major, placing emphasis on the words "liebes" (dear) and "geh" (go).

Though the Erlking's seductive verses differ in their accompanying figurations (providing some relief for the pianist), they are still based on triplets, not letting the daemonic presence be forgotten.

The chromaticism in the son's melody indicates a call to his father, creating dissonances between the vocal part and the bass that evoke the boy's horror.

The piano accompaniment transforms into flowing major arpeggios that may refer to the dances of the Erlking's daughters and the troubled half-sleep of the child.

He threatens the boy, the initial lyricism and playfulness yielding to a measured declamation, with the "passing note motif" being voiced both in the treble and in the bass.

[13] The grace notes in the voice line suggest the father's horror, and the music accelerates on the words "er reitet geschwind" (he swiftly rides on).

[14] The recitative, in absence of the piano, draws attention to the dramatic text and amplifies the immense loss and sorrow caused by the Son's death.

[17] However, when Wilhelmine Schröder-Devrient performed "Erlkönig" before Goethe in 1830, he is reported by Eduard Genast to have said: "I have heard this composition once before, when it did not appeal to me at all; but sung in this way the whole shapes itself into a visible picture".

[2] Dietrich Fischer-Dieskau has highlighted the piano accompaniment in the setting, which he describes as having a "compositional life of its own", with important motifs such as the repeated octaves that create an eerie, suspenseful atmosphere.

Like Beethoven's Fifth Symphony it appeals to the great unwashed and the squeaky-clean in equal measure, to those who see something symbolic in the poem, and to those who simply love a rattling good yarn excitingly told.

"[22] The piece is regarded as challenging to perform due to the multiple characters the vocalist is required to portray, as well as its difficult accompaniment, involving rapidly repeated chords and octaves.

Compared to the original, Liszt retains many of the basic musical elements, including melody, harmony, accompanimental patterns, and dynamics.

"[26] Commenting on Liszt's arrangements of Schubert's Lieder, Robert Schumann wrote: "[they] have found a great deal of interest among the public.

[28] The work is characterized by its highly polyphonic nature, the solo violin having to perform the narrator, the Erlkönig, the father, and the child (4 independent voices) in their different vocal colourations, but also the complete piano accompaniment at the same time.

As recalled by Berlioz in his memoirs, the two composers were soon drawn into an argument comparing Tomášek's composition to Schubert's: "Someone (for there are people who find fault with everything) drew a comparison between the accompaniment of this piece and that of Schubert's ballad, in which the furious gallop of the horse is reproduced, and declared that M. Tomášek had mimicked the placid gait of a priest's nag.

An intelligent critic, however, more capable than his neighbours of judging of the philosophy of art, annihilated this irony, and replied with great good sense: 'It is just because Schubert made that unlucky horse gallop so wildly that it has foundered, and is now forced to go at a foot pace.

Berlioz's biographer Jacques Barzun wrote of the arrangement: "From the finely wrought and polished score no one could suspect anything of the anxiety, illness, or conflicts in his heart and soul.

[32] Liszt's arrangement is scored for two flutes, two oboes, two clarinets, two bassoons, two horns, two trumpets, timpani, harp, strings, and solo voice.

He wrote: "To my ear, it is often a real insult to have to listen to a singer, following an orchestral piece in a gigantic hall, performing lieder to the spindly accompaniment of a piano in the huge space.

"[33] Reger's arrangement of "Erlkönig" was completed in 1914, together with "Gretchen am Spinnrade", "Gruppe aus dem Tartarus", "Prometheus", and "Gesänge des Harfners".