Classical: Still so controversial, still so new

In the early spring of 1869, news reached Richard Wagner in his Swiss hideaway that Hector Berlioz had died, and he briefly considered laying aside his work on Siegfried to write a memorial essay.

After all, hearing Berlioz conduct his dramatic symphony Romeo et Juliette and Grande Symphonie funebre et triomphale had been revelations of his, otherwise, none-too-happy sojourn in Paris between 1839 and 1842. And in the spring of 1855, when the two composers found themselves conducting rival concert series in London, they had become quite convivial friends. True, when Berlioz later declared himself baffled by the chromaticism of the prelude to Tristan und Isolde, relations had cooled. Yet the reason Wagner decided not to write that essay after all seems to have been something else, implicit in the very topic he had proposed for himself: "Berlioz, the giant-sized pupil, too great to find himself a master".

He was neither the first, nor by any means the last great composer to find Berlioz's musical language, for all its excitement and grandeur, somehow lacking, unschooled, irredeemably odd. Mendelssohn, meeting Berlioz in Rome as early as 1831, dismissed his efforts as "without a spark of talent; groping around in the dark, he deems himself creator of a new world...".

In 1903, Debussy went so far as to describe Berlioz as "a monster. He is not a musician at all. He creates the illusion of music by means borrowed from literature and painting", though he actually admired the Symphonie fantastique and, like Brahms, was fond of L'Enfance du Christ. Stravinsky was more specific: "No orchestral skill can hide the fact that Berlioz's basses are sometimes uncertain and the inner harmonic voices unclear... and balance is regulated superficially by dynamics." To which Boulez could only add: "There are awkward harmonies in Berlioz that make one scream; it is easy to see that he plucked out his chords on the guitar and could hear almost nothing."

No wonder, then, that only three years before the bi-centenary of Berlioz's birth, the writings and utterances of such eminent Berliozians as David Cairns, who has just completed his magisterial biography, Professor Julian Rushton, author of the most searching study of Berlioz's musical language, and Sir Colin Davis, as he embarks on his latest Berlioz cycle, retain the embattled conviction of a cause.

On one matter, though, fans and detractors would surely agree: the almost unprecedented circumstances of Berlioz's emergence. Up at least until the 19th century, musicians almost always came to composition by way of youthful performing experience in choirs or - as in the cases of the Gabrielis, Purcells, Couperins and Bachs - because it was the family business. Berlioz seems to have been the first major figure to conceive a passion for becoming a composer before he had any real idea of what it entailed.

Educated at home in a remote corner of provincial France, he picked up the rudiments of notation from his father, and of harmony from a stray textbook, while acquiring a reasonable skill on the flute and guitar (though never the piano) from visiting musicians who also helped him to try out his earliest compositional efforts. But not until he arrived in Paris in 1821, a reluctant 17-year-old medical student, was he able to see his first opera, hear his first orchestra or even begin exploring the then known repertoire.

In due course, he would find an encouraging mentor in the minor composer Jean Francois Lesueur and take lessons in fugue at the Paris Conservatoire. Yet essentially, he continued to teach himself, hastening, scores in hand, night after night to the Opera to pursue his new-found enthusiasm for Gluck, Spontini and Weber, or to the Conservatoire concert-hall to catch up on the revolutionary symphonies of Beethoven.

It speaks volumes for his innate gifts and quick intelligence that, despite the belated patchiness of his training, he was composing choral and orchestral pieces which already sound striking within a couple of years of arriving in Paris, and that he was able to loose upon the world a work of such dazzling brilliance and originality as the Symphonie fantastique at only 26.

Yet because early circumstances had deprived him of the experience of most earlier composers - of taking in the basics of melody, harmony, counterpoint, repertoire and performance more or less with their mothers' milk - he developed little sense of how music itself can beget music: how the personal reworking of a traditional technique or the transformation of an admired model can produce something both satisfying and new. Almost without exception, he required some "external" inspiration to set him going: a dramatic or sacred text, a visual or poetic image, some grand public occasion or searing private passion. And almost all his large- scale projects, including those ostensibly labelled symphony, opera or mass, comprise strange hybrids of genre, form, style and technique straining towards some ultimate synthesis which, apart from the Symphonie fantastique, he achieved on every level perhaps only once more, paradoxically, in his most hybrid concept of all: the near-miraculously balanced sequence of picturesque, dramatic, intimate and apocalyptic scenes comprising his "concert opera" La Damnation de Faust.

If this was one occasion when Berlioz managed to turn the very idiosyncrasies and limitations of his technique to positive account on the largest scale, his less equally achieved works are full of moments, passages, whole movements which suggest the same propensity in varying degrees of detail. Few have ever questioned his special gift for sustained, often strikingly asymmetrical melody, though more have agreed with Ravel's complaint that Berlioz was "the only composer of genius who conceived his melodies without hearing their harmonisation", and that the chords he added afterwards often sounded ad hoc or arbitrary. Yet out of this very disjunction of melody and harmony, Berlioz was able to create substantial spans of continuity and contrast by harmonising the melody in several different ways at various stages of a piece.

There are times too when Berlioz seems to generate his compositional substance by superimposing not only melody and harmony, but also rhythm and orchestration as if they were semi-autonomous elements; developing obsessive rhythmic ostinatos or nervy cross-rhythms with an inventiveness that looks forward to Stravinsky who himself was prepared to concede that, orchestrally, Berlioz "had the perfect imagination of each new instrument he used, as well as the knowledge of its technique".

Maybe it was his limited ability to conceive ideas, textures or structures as a whole that led to this alternative way of composing, as it were, by layers; and there are certainly times when the elements seem to get "out of sync", when the rhythms seem to trip up the harmonies, or the texture throws up some colouristic novelty he seems not to know what to do with.

Yet it could be argued that it was precisely this limitation that opened the way for his most striking innovation of all: the substitution for the "organic" process of thematic development which he never entirely mastered, by the "inorganic" but often supremely exciting device of juxtaposing and superimposing quite contrasting ideas or textural layers - ranging from the almost Ives-like concatenation of polymetric fanfares at the climax of the "Royal Hunt and Storm" tableau of Les Troyens to the creation of entire forms, as in the scherzo of Harold en Italie, where two different tempos are laid out, then superimposed with still a third tempo on top. Whether taken into the symphonic process itself by such successors as Mahler and Richard Strauss, or developed even more rigorously as in the Turangalila-symphonie of Messiaen (who regarded Berlioz as simply "Le plus grand compositeur du monde"), the ubiquity of this compositional device today is just one of the reasons why Berlioz still seems so immediate, so controversial, so ever-new.

The year-long Berlioz Odyssey, 17 concerts by the London Symphony Orchestra conducted by Sir Colin Davis, opens with a concert performance of `Benvenuto Cellini' at the Barbican (0171-638 8891) on 5 Dec (repeated on 8 & 11 Dec). Information and online booking at www.lso.co.uk