That's an extraordinary thought, that Sibelius could have written the piece without those usually essential markers of time to manage his musical imagination. The rest of the score was in pencil, but the bar-lines, those dividers of musical time, had seemingly been written after Sibelius had written down the notes, in a thick red pencil, and in impressionistic, curved lines rather that straight, rigid marks. Seeing the symphony in the flesh revealed something even more intriguing than the liquid fluency of Sibelius's handwriting. I found a clue when I went to the Sibelius Museum in Turku in Finland, where the manuscript of the symphony, one of Finnish music's holiest of holies, is housed. Photograph: Alfredo Dagli Orti/В© Alfredo Dagli Orti/The Art Archive/Corbis

The autograph score of opening page of Sibelius's Sixth Symphony, kept in the Sibelius Museum. Yet if all that's true, how is it that it's this piece - not the more obviously radical Seventh (which Sibelius compresses into a single 20-minute movement), or the single-mindedly dissonant Fourth - that is the single most influential of Sibelius's symphonies for later generations of Finnish composers, such as Magnus Lindberg and Kaija Saariaho? Instead, this is music that's so self-effacing it's the equivalent of going for a walk in the snow and covering up your tracks, a symphony that seems to want to leave no mark in the musical landscape at all. How could you write a symphony that seemed, if anything, to retreat in musical time to an era before tonality, a symphony of weird modes and ambiguous scales? And how could you conceive a work that seemed to be about so little: a tension between the scales of C major and a modally inflected D minor, which ends even less demonstratively than it began, with a pianissimo chant for the strings and timpani, music that's the opposite of grandiloquent resolution (such as the end of Sibelius's previous symphony, the huge chords that wrench the Fifth Symphony to a conclusion). Sibelius may have thought of it as a purifying corrective to a musical world of modernist angst, but perhaps it was that very plainness that perplexed Britten. The economy of Sibelius's material, its avoidance of anything approaching emotionally charged rhetoric or expressionist trauma, its repudiation of any ultra-modern clichГ©s, mark this as a very strange symphony indeed for 1923. Jean Sibelius - manipulating music's fourth dimension.

Sibelius 5 imslp