Not so strange, actually. Since its publication four years before, Sibelius's morbid little morceau had become a hit with every spa band and hotel trio in Europe, vastly to the enhancement of his fame if not his fortune - for in a parlous moment he had virtually signed his rights away. No doubt part of the Valse's popularity sprang from its macabre story-line. Sibelius had originally composed it to accompany a scene in a play entitled Kuolema (Death) by his brother-in-law Arvid Jarnefelt, in which a mother is seen rising from her sickbed to dance her youthful memories until Death knocks at her door - a typical instance of the fin de siecle fatalism that saturated the early paintings of Munch, the plays of Strindberg and Richard Strauss's Salome. But it also reminds us how much the rise of Sibelius owed to the theatre, for both the Karelia Suite (1893) and Finlandia (1899) itself were spin-offs from a Finnish tradition of patriotic pageants - comprising, with Valse triste, what is generally mis-called "incidental" music.
Whoever first thought of that term - with its implications of something applied, inessential, unimportant - deserves a posthumous custard pie. Even leaving aside the integral part music evidently played in Ancient Greek drama, the Medieval Mysteries and the Elizabethan theatre, even forgetting Purcell's cornucopia of act tunes, songs and dances, and focusing on the 19th and early 20th centuries, one quickly tots up the glorious tally of Beethoven's music for Goethe's Egmont (1810), Schubert's for Von Chezy's Rosamunde (1823), Mendelssohn's for A Midsummer Night's Dream (1843), Bizet's for Daudet's L'Arlesienne (1874), Grieg's for Ibsen's Peer Gynt (1876), Faure's for Maeterlinck's Pelleas et Melisande (1898), Vaughan Williams's for Aristophanes' The Wasps (1909) and Debussy's for D'Annunzio's Le Martye de Saint Sebastien (1911).
Only since the First World War, and despite the continuing concern of such dramatists as Brecht to involve music in their plays, has the practice of commissioning not-so-incidental music from major composers seemed to languish - partly because theatres could no longer afford sizeable orchestras, partly because such work has fallen increasingly into the hands of specialists, such as the Royal Shakespeare Company's Guy Woolfenden. It could, of course, be argued that the tradition has passed to the cinema. But the interweaving of speech and music in a mechanically reproduced medium like film is hardly the same as the impact of live music upon live action in the real theatre.
Has something substantive been lost? The theatrical career of Sibelius is suggestive. At the outset, he had wanted to write opera proper, and with his innate command of large-scale motion, plus his deep feeling for the mythological world of the Kalevala, he might have been expected to evolve into a kind of Finnish Wagner. In 1893 he actually embarked upon a full-scale opera, entitled The Building of the Boat, for which The Swan of Tuonela was intended as the prelude. But after a trip to the Bayreuth and Munich Wagner festivals of the following year, he lost heart, and the one short opera he did complete, but never published - The Maiden in the Tower (1896) - suggests why. For all his ability to whip up climaxes and paint tone-pictures, he evidently lacked the gift for timing and articulating the cut and thrust between stage characters. Thenceforth, his feeling for structural motion was to be realised in the symphonies, his mythological affinities in the tone-poems, and his dramatic ambitions over the next 30 years in some 10, often substantial, scores for the spoken theatre.
Part of this prodigality is doubtless explained by the fact that, as the centre of a bilingual nation, Helsinki sustained two national theatres. Sibelius himself was born into the Swedish-speaking minority and only learnt Finnish in his adolescence. But the musical demands of the typical turn-of-the-century theatre peculiarly suited his talents. The not infrequent need for quite substantial, self-contained pieces such as overtures, act- preludes and intermezzos not only drew upon his symphonic strengths, but enabled him to recycle extensive suites for the concert hall. Indeed, the six orchestral movements, including a spacious opening Nocturne, which he derived from his music for Adolf Paul's play King Christian II (1898) were among his first international successes. Finer still are the nine- movement Suite (1905) for Maeterlinck's Pelleas et Melisande - including its majestic "Castle Gate" music, translucent Pastorale and affecting death scene - and the less familiar but often magical seven-movement Suite (1908) for Strindberg's Swanwhite.
On the other hand, there were dramas that drew upon his uncanny ability to evoke colour, atmosphere, space, with a mere handful of notes. The over-an- hour-long score he wrote for Shakespeare's Tempest in 1926 comprises no fewer than 34 music cues, and it is fascinating to hear how he later combined, re-worked and amplified some of the slightest of them into his two Tempest concert suites. Meanwhile, more modest commissions involved him in the writing of short character pieces, marches, dances and what not, in song-settings and so-called melodrame (or music to be spoken over): all of these preoccupations also of his work for the concert hall and the community. One of the special pleasures of the vast on-going project of the BIS label to record every scrap of Sibelius has been the recovery of some of these more fugitive theatre pieces - for instance, the Wedding March he composed for another Adolf Paul play The Language of Birds in 1911, but never published. This proves a gem: a kind of Weber-esque processional glimpsed through the mists, yet proclaiming Sibelius in every idiosyncratic detail.
And the latest release in the series (BIS CD 735), recorded by the Lahti Chamber Choir and Symphony Orchestra under Osmo Vanska, is a revelation. In 1916, while revising his Fifth Symphony, Sibelius completed a 40-minute score for the Finnish premiere of Hugo von Hofmannsthal's reworking of Everyman, including, uniquely in his orchestral output, parts for piano and organ. Unlike the exotic music for Hjalmar Procope's Belshazzar's Feast (1906) which fills out the disc, Sibelius never extracted an Everyman suite, believing the music to be too intricately subservient to the text. And listening to the tiny folkloristic interruptions to the Act 1 feast scene, one hears what he meant. But the later stages are far more continuous. For the scene in which the dying Everyman parleys with the allegorical figure of Good Deeds, Sibelius spins a strange, near-atonal web of drifting polyphony for strings, pre-echoing nothing so much as the finale of Vaughan Williams's Sixth Symphony some 30 years in the future. Thence, by way of a more baroque-style church scene and a sequence of anguished chromatic spasms for the confounding of the Devil, the music evolves into a hieratic "Gloria in excelsis" as Everyman's soul is saved. One thinks of Sibelius as a Pantheistic rather than Christian artist, yet the "old Slavonic"- style chantings and chimings of this final tableau strikingly anticipate the kind of sacred manner that Janacek, Szymanowski and Stravinsky were to approach only over the ensuing decade. The theatre may not have engaged the depths of Sibelius's art, but it surely, and vitally, broadened his scope.