It is a timeless movement, inexorably, naturally propelling its way. Nothing prepares one for the shift into the original second movement, the Allegro moderato, which Sibelius seamlessly joins to the first. And nothing prepares one for the burst of energy which drives the movement with brassy splendour to its end. And yet, throughout, there is no sense of a break, no sense that there has been a "change." It is as if continents have sailed their way across the earth, changing climates, changing flora and fauna, and yet the land remains the same.

But the composition, growth and final manifestation of this symphony was not easy for Sibelius. Although he was an avid (and sometimes pained) revisionist of his own works, self-critical as he was, no other work of his had to endure so much revision.

THE TIME was 1914 - Stravinsky's Rite of Spring had already rocked Paris, and Schoenberg was.... well, making his reputation as Schoenberg. Sibelius was working on his Fifth, Sixth and to some extent his Seventh Symphonies at the same time.

Sibelius, when you think about his music, does not fit into the picture here. Placed against these "modern" contemporaries, one is easily tempted to believe that Sibelius is an old-fashioned Romantic. Yes and no. Unlike the "high modernists", Sibelius still composed music that is on the surface optimistic and melodic; but like his counterparts, he too was aware of the renewed 20th century interest in the neo-classical ideal of form. Nevertheless, faced with the onslaught of the multi-faceted "modernist" era, Sibelius sought to realign his perspective towards his position as a composer.

It is often thought that the essence of a symphony lies in its form, but this is certainly not the case. The content is always the primary factor, while form is secondary, the music itself determining its outward form.

By saying this, Sibelius does not discount the importance of form (in this case, the form of the symphony as genre), but places it at the logical service of content. Content being the musical substance, or the theme which is the basis of a piece of music. This then, is exactly what "organic growth", which we Sibelians like to talk about, is based upon. The form of the cell, which makes up the body, is 'meaningless' unless it has a content, a personality. What are we without our personalities except empty vessels, mechanicals.

Our personality modifies our basic form; how we react to the world moulds the basic form which nature gives us, in order that we can handle that world. This piece of Darwinism is naturally kin to Sibelius' brand of musical evolution, of organic symphonic development.

Perhaps then, the reason why Sibelius' music remains so directly appealing, so lyrical and accessible, is simply because to him, content is king. He comes up with the theme(s) first, before he allows it to evolve into a symphony. This is in direct contrast to the absolute formalists, who allowed the theoretical concepts of form (eg. serialism, minimalism) to determine its content (which is secondary).

Having created a theme, Sibelius' job was to determine how the theme "struggled" into and towards its "final" form.

On April 10th, 1915, Sibelius wrote in his diary:

Spent the evening with the [Fifth] symphony. The disposition of the themes: with all its mystery and fascination, this is the important thing. It is as if God the Father had thrown down mosaic pieces from heaven's floor and asked me to put them back as they were. Perhaps that is a good definition of composition. Perhaps not. How should I know?

Clearly, Sibelius himself was struggling with his own paradigm of composition. What is composition? In his diary, he highlights the "disposition" (personality) of the themes - which are "mysterious" and "fascinat[ing]". The mosaic pieces (themes) are there before him, but their final form (imagine a completed jig-saw puzzle) eludes him until he has "composed" them together.

"Perhaps that is a good definition of composition. Perhaps not." Sibelius himself could not be sure - the magic of composition is an eternal mystery, as is the magic of nature's life.

"How should I know?" This query is crucial in understanding Sibelius' self-critical nature and his revisionist tendencies. No one subscribing to Sibelius' paradigm can easily say "My composition is finished". Why? Because one cannot easily know that a content has reached its most optimum form. Is there such a thing as a final end? Can we stop evolving one day and say, the human form is now perfect, and does not need to change any more? The same query surfaces when Sibelius composed/evolved a theme towards symphonic perfection - how does he know when it has reached the "correct" form?

I don't think even he could or would answer this question (Sibelius did not like to talk about his compositional processes). But we can see aspects of the answer in his symphonic canon. One answer lies in understanding perhaps the most perfect of his symphonies - the Seventh. Another answer lies in understanding the evolution of the Fifth.

On 30th July 1914, Sibelius' old friend and supporter Axel Carpelan wrote to him: "...[L]isten to your own inner promptings... Follow your own star and stick to the symphonic path." The composer strengthened his position.

SIBELIUS HAD been racing against time to complete the symphony to be performed at his 50th birthday concert celebration. When the symphony was first heard in December 1915, it comprised four movements.

It was played with a 50-member ensemble, the newly formed Helsinki Philharmonic Orchestra. This ensemble was created when the Philharmonic (or National) Orchestra of Robert Kajanus and the Helsinki Symphony Orchestra of Georg Schnéevoigt, both rivals, buried the hatchet and united in 1914. But oops, the First World War also broke out - the more than a hundred members of the orchestra were reduced to 50-something as the German musicians went home.

The Fifth Symphony (1915) was premiered by the composer and the orchestra (see photo above right) on 8 December, Sibelius' 50th birthday. After the performance, Robert Kajanus delivered a speech, proclaiming:

As far as our Finnish music is concerned, it scarcely existed when Jean Sibelius struck his first powerful chords... Barely had we begun to till the barren soil, when a tremendous sound arose from the wilderness. Away with spades and picks. Finnish music's mighty springs came bursting forth. A great torrent burst forth to engulf all before it. Jean Sibelius alone showed the way.

This quotation seems simple enough, with almost clichéd "Romantic" images. But are they coincidental, this exact choice of phrases? Away with the "spades and picks" of human artifice; there is no need for these formal tools. Instead, the sound arises from the "wilderness", Finnish music's "mighty springs" is a great torrent bursting forth from nature.

Perhaps I am over-reading things, but indulge me. The story of the Fifth Symphony is immersed in a great many diary entries and quotations from the composer, many appearing to be nothing more than innocent Romantic exclamations at the wonders of nature.

On November 13, 1914, Sibelius had written in his diary another one of his heartfelt bits of literature which beautifully fuses nature's beauty and his own emotions:

I have had a wonderful idea. The Adagio of the symphony - earth, worms and heartache - fortissimos and muted strings, very muted. And the sounds are godlike. Have rejoiced and revelled in rushing strings when the soul sings.

Earth, worms and heartache. Time and time again, we Sibelians must assert how one cannot underestimate the power, influence and love that existed between Sibelius and nature. In his hands, the very wet earth sings.

This planned Adagio was not, in fact, realised. In its place was the Andante mosso, quasi allegretto as we know it today. A tender and lyrical work still. Over a light orchestral field of soft grass, the woodwind and strings take turns to gently weave a lightly treading theme that, as if reaching the top of a hill, watches the beauty of the sky unfold a lyrical and nostalgic melody over the strings. Hints of the next movement's mighty "Swan Hymn" appear inconspicuously on the basses and brass.

One day, on his routine walk through the countryside, Sibelius watched as sixteen swans flew overhead, a sight which took his breath away:

One of my greatest experiences! My God what beauty! ... Their call the same woodwind type as that of cranes, but without tremolo. The swan-call closer to trumpet, although there is something of a sarrusophone sound. A low refrain reminiscent of a small child crying. Nature's Mysticism and Life's Angst! The Fifth Symphony's finale-theme: Legato in the trumpets!

This momentary encounter with nature's glorious beauty evidently inspired the awe-inspiring yet gently heroic swinging horn theme of the Fifth Symphony's finale. The orchestral strings summon a great ascending wind of energy before the mighty breaths that nature breathes into the horns begin their song. Axel Carpelan called it, after the composer's own image, "the incomparable swan hymn" (Dec 15, 1916).

The swinging horns are soon joined by a long-breathed melody on the woodwinds, which intone a beautifully simple hymn-like theme above the undulating current of basses. As the swans soar into ever higher spheres of living spirit, Sibelius modulates the potent music into a glorious C major, creating what many have acknowledged as one of the most magnificent and affirmative climaxes in music.

THE ORIGINAL 1915 version is in many senses quieter and not as bold as the final version. For example, the dawning horn-call of the opening is missing. Instead, you have a serene sky of soft horns where, almost tentatively, the woodwinds call out to each other. Even more significantly, the original Fifth is darker. I don't mean to say that the music sounds less "tonal" or is more sad. Rather, the contrast between sections of light and darkness is much greater.

If the final Fifth is "light/dawn", and the Fourth Symphony is "dark/dusk", then the original Fifth is a magical aurorae of wavering darkness and light, full of mystery. It encapsulates the organic-musical link between the "bleak" Fourth and the optimistic Fifth, a bridge that I had been looking for for years.

I have never understood why so many commentators have called the original Fifth startlingly different from the final. To me, the feeling of kinship between these "twins" was immediately recognisable. You can see the way the original "grew" into the final version.

Despite its ethereal floating chords and textures, the magical rushes of quiet wonder, some critics have called the original version "uneventful", "rhythmically unfocussed" and generally less forward in character. To me, these are elements of subtlety, and speak of Sibelius' ability for economy of expression with maximum effect. The 1915 version is more "innocent", drifting mistily for the home of its final form.

By the end of 1915, Sibelius had become disillusioned with the symphony. On 26 January, 1916, as he worked on the first revision, he wrote:

I must confess I am working again on Sym.5. Struggling with God. I want to give my new symphony a different, more human form. More earthy, more vibrant.

That is exactly what happens by the time the 1919 version appeared. But before that, troubles continued. On his 51st birthday, the 1916 version was premiered to mixed reviews. Only a double bass part survives of this score, but we know that the original first two movements have already joined.

In May 1918, Sibelius had proposed writing a new first movement for the symphony, but he decided against it in February 1919. In a letter to Axel Carpelan:

These days have been very successful. Saw things very clearly. The first movement of the Fifth Symphony is one of the best things I've ever written. Can't understand my blindness.

The spiritual and musicological support from Axel Carpelan (right) was of great importance to the composer, and in many ways have helped give us the Fifth Symphony as we hear it today. His death in March 1919 affected Sibelius greatly:

How empty life seems. No sun, no music, no affection. How alone I am with all my music... Now Axel is laid to rest in the cold earth. It feels so immeasurably and profoundly sad. For whom shall I compose now?

A misterioso section follows the Swan Hymn. The muted violins create a shimmering field of light and mist while the flute quietly reminisces its hymn. Beneath this, the basses intone undercurrents of energy, sounding like the deep breaths that heave in nature's forests, mountains and seas. An earthly heartbeat. An ocean's breath of life.

In its transformation, the Symphony did indeed become more vibrant - its energy is more direct, its brilliance more staggering, its drive unstoppable, its very life more glorious. Halfway through the finale, the mood turns melancholy once again, and I cannot help but wonder if somewhere during the final revision, Sibelius had turn his thoughts once more to his departed friend, to his heart full of sadness, to nature's mysticism and life's angst, perhaps even towards all of humanity in the year after the war, and last but not least, the birth of Finnish independence. Here then, was the final Fifth, in more "human" form.

They say silence can be deafening. Here, in this symphony, lies one of the most unique endings in music. As the music revives the Swan Hymn on the trumpets, triumphantly ascending out of the darkness, the symphony drives the music into a conclusion comprising six massive orchestral chords. But these are not the hammer blows of death, but the affirmations of life.

SIBELIUS SAID that when he finished revising the final version of the Symphony, at the moment he laid down his pen, "twelve white swans settled down on the lake, and then circled the house three times before flying away."

Was it truly finished? In April 1919, Sibelius' cast doubt once again even as the final version approached 'finality'.

Have cut out the second and third movements. The first movement is a symphonic fantasia and does not require anything else. That's where it all began!!! Shall I call it "Symphonie in einem Satze" ["Symphony in one movement"] or "symphoniesche Fantasie: Fantasia sinfonica I"?

Where have we heard this before? Yes, the Seventh Symphony. Sibelius had already realised that "here" is where it all begins - the idea, the concept of the continuous symphonic singularity which is part symphonic development, part "fantasia" of evolving themes.

Even as the Fifth Symphony approached 'completion', it had already more than prophesised the beginning and continuation of its symphonic essence. The Fifth is but an aspect of the Seventh; these are not merely individual symphonies, but overlapping and interweaving levels of an unparalleled symphonic journey that began in the earth, and developed into the Seventh and Tapiola.

DECADES AGO, as Sibelius passed from this world, Sir Malcolm Sargent would have directed the Helsinki Orchestra in the six hammer blows.

As the orchestra forges each chord into the being of sound, the silence between each chord reverberates in the ears, in the spirit, proclaiming the mysticism of nature's voices and the pain of life in all its ephemeral beauty. But life, like the search for symphonic perfection, symphonic life, goes on.

As Sibelius died, his Symphony lived; and as his Symphony died, Sibelius lived.