The Finnish government commissioned Sibelius to write the symphony in honor of his 50th birthday, 8 December 1915, which had been declared a national holiday.

During his creative process, Sibelius wrote in his diary: "It was as if God the Father was throwing pieces of mosaic from the edge of heaven and asking me to figure out what the pattern was.

"[4][5] The original version of the work was premiered by the Helsinki Philharmonic Orchestra, conducted by Sibelius on 8 December 1915, his 50th birthday.

The final version, which is the one most commonly performed today, was premiered again by the Helsinki Philharmonic, conducted by Sibelius, on 24 November 1919.

[5] The first version of the new symphony kept much of his familiar orchestral style (consonant sonorities, woodwind lines in parallel thirds, rich melodic development, etc.)

Though he had been in the public spotlight for nearly twenty years, Sibelius found his works receiving poor reviews for the first time with the 1911 premiere of his Symphony No.

5 on television in 2018, said that Sibelius seems to have made a definite choice, a year or two after his previous symphony, to stay within the frames of harmonic language of late-19th-century romanticism; instead he would innovate in the realms of macrostructure and instrumental colouring.

Sibelius originally intended this to be two separate movements, but linked the slower introduction with the faster, waltz-like "scherzo" section to create a single form.

Sibelian scholars – Cecil Gray (1935),[10] Gerald Abraham (1947),[11] Simon Parmet (1955),[12] Robert Layton (1965),[13] and James Hepokoski (1993)[14] – have their disagreements and individual ideas as to the movement's formal divides.

They debate such points as its separation into two movements, the existence of two expositions, how to functionally describe the Scherzo and Trio, and the exact location of the beginning of the recapitulation and coda.

He explains the distinctly melodic section beginning at the Allegro moderato as a Scherzo and Trio used as a substitute for the second half of the development.

Through this analysis Hepokoski maintains the general location of sectional changes described by the earlier musicologists and agrees that the movement can roughly be analysed in sonata form.

Furthermore, after this meter change, where rehearsal letters should continue from N to the end of the alphabet, they return to A, a clear sign of a beginning of a new movement.

More recent musicologists disagree with this separation into two movements on the grounds that both sections are based on the same material and in combination allow for analysis in sonata form.

The gradual accelerando, which begins at the end (the climax) of the opening Tempo molto moderato and leads into the Allegro moderato Scherzo, continues uninterrupted to the end of the movement; indeed, without access to a score, it is difficult for the listener to identify exactly where the Scherzo section begins.

At measure 28, the fourth theme enters still in G major and distinguished by its duple (equal) subdivision of the beat in the horns and woodwinds as a chorale-like chord progression.

What follows is a developmental section (what Hepokoski calls Rotation 3) based on the insignificant transition that anticipated the string entrance before the B-group in the first exposition.

The texture also changes as the melody fades away and the strings begin a long rising tremolo figure as related to the woodwinds' sixteenth-note pattern of the second theme.

Stedman[15] adds to Abraham's analysis by explaining that this return to the Scherzo acts as a recapitulation to the overall sonata form structure.

He explains that "while not denying the Scherzo-like character of many episodes in the second half of the movement, there is no doubt that it does in fact correspond in broad outline to the recapitulation normal in sonata form."

When defining the location of the recapitulation within this rotation, he is unable to give specific measure numbers because it enters in a staggered manner.

An equally plausible[citation needed] starting place is measure 497 (6 bars before Q) at the end of the final statement of the chordal duple-rhythm B-group theme (which begins at measure 487, letter P) with its fff syncopated trombone statement of the first four rising notes of the A-group (with which the work began) and the beginning of the E♭ pedal which continues to the end of the movement.

This entire ending section races in quarter-note arpeggios towards the conclusion, thus making it difficult to pinpoint the exact location of the beginning of the coda.

[citation needed] This quiet movement is a set of variations on a theme of the flute heard at the beginning on the strings, played pizzicato with chirping woodwinds to create a cheerful feeling.

After this is developed, a swaying, triple-time motif begins in the horns, which is said to have been inspired by the sound of swan-calls, as well as a specific instance when the composer witnessed sixteen of them taking flight at once.

Straightforward appropriation can be heard in the coda of "Beach Baby" by The First Class (1974); the main song of the movie The Small One (1978); "Since Yesterday" by Strawberry Switchblade (1984); "I Don't Believe in Miracles" by Sinitta (1988); "Oh What A Life" by Play People (2008);[20] and "The Nek"[21] by Stephen Rae for the 2015 Australian miniseries Gallipoli.