It sounds too much like a film script to be true. An aspiring young composer composes a massive work for chorus and orchestra that he believes will make his reputation. But during his life-time the score disappears, burnt by the now-dissatisfied composer – gone, it seems, for ever. A century-and-a-half later a patient, modest musician stumbles on a thick manuscript hidden in an organ loft and copies it out by hand. And finally the music rings out, in televised glory, all over Europe.

But it's true, every word of it. The composer was Berlioz, and the work is his Messe Solennelle. In 1824, the year in which this unlikely tale begins, he was a mere twenty-year-old, sent to Paris to study medicine to become a physician like his father, but learning music in the teeth of parental opposition. So when he was commissioned by the choirmaster of the church of St. Roch in central Paris to write a Mass for the Feast of the Holy Innocents in late December, it came as a godsend: here was the opportunity to prove himself. He plunged himself into the writing of the Mass, producing a score hugely ambitious for such an inexperienced composer: fourteen sections in all, an hour in length, with extended choral writing and important solos for soprano, tenor and baritone. But the first proposed performance came to nothing: the parts, copied out by the St. Roch choirboys, were full of errors, and large sections of the orchestra simply failed to materialise at the sole rehearsal. The only possible action was to cancel the perfomance. Berlioz learned from the débâcle. He tried again, borrowing some money to make sure of his orchestra, and this time the parts were in better order. The performance finally took place in July of the following year, and the young composer, relieved and proud, could appease his family with the news that his Messe Solennelle was a resounding success with public and press alike.

The work was performed a few more times during Berlioz's lifetime. The composer revised the music and then his opinion of it and, as he claims in his Memoirs, burned it. It was presumed irretrievably lost, along with the few other works he had composed around the same time. And then in 1991, through an extraordinary concatenation of coincidences, a middle-aged Belgian teacher called Frans Moors was looking through a pile of scores in the organ loft of the church of St. Charles Borromeo at Antwerp, Belgium, when he came across something that aroused his curiosity. Mr Moors, shy, quietly spoken, bespectacled and bearded, takes up the story himself. "I was looking for a score of Mozart's Coronation Mass in the organ loft. I had been a pupil of the organist there when I was a boy; he told me once that I must learn to accompany, and that the best way of learning anything was by doing it. So I had already accompanied the Coronation Mass, and in 1991, the "Mozart Year", I was going to accompany a soprano in some extracts from it. I had moved away from Antwerp, but I remembered that there was a score of the Coronation in that cupboard. I went through all the scores there looking for the Mozart and I noticed this thick green volume – the thickest in the cupboard – with "Messe Solennelle, Hector Berlioz' in a red label on the spine. Since I am a choirmaster I wondered whether there might be something in it for my choir, although flicking through the pages I knew it wasn't for my singers. But I could see that it was something interesting and I asked the church for permission to copy it out. I know the Berlioz that every music-lover knows – the Symphonie Fantastique, Harold en Italie, Carnaval Romain, that sort of thing – but I didn't know that he had composed a Mass. So I read his Memoirs, and it was there that I found he said he had burnt it but that he had kept a small part, the "Et Resurrexit". I then found out that the "Et Resurrexit" was in print and that it was published by Breitkopf & Härtel. I looked out the score in the Conservatoire at Antwerp, and compared the printed version with "my" Mass. They were the same, which persuaded me that I had discovered the Mass that had been burnt, the Messe Solennelle. I looked for a conductor to show it to, but couldn't find anyone in Belgium. The next year I was on holiday in France. I was listening to France Musique when I heard an announcement that Philips were going to release a complete Berlioz with John Eliot Gardiner. When I got home from holiday, I learned from a colleague, again by chance, that Bärenreiter was the publisher of the complete edition of Berlioz. So I wrote to Bärenreiter and to Philips. Bärenreiter immediately sent an expert" – Hugh MacDonald, the foremost living Berlioz scholar – "to check that it was an original work, and he said, yes, it was."

How the music got to Antwerp seems to be easily explained, thanks to a note at the bottom of the score: "The score of this Mass, entirely in the hand of Berlioz, was given as a souvenir of the old friendship which linked me with him, [signed] A. Bessems, Paris 1835". Antoine Bessems was a composer and violinist who, though born in Antwerp, in 1809, lived most of his life in Paris. Hugh MacDonald speculates that he may have taken part in the second performance of the Mass, in 1827 and, later, may have been given the score in return for his services in the concerts Berlioz gave in Paris in 1835. When Bessems died, in 1868, the manuscript went to his brother, Joseph, who was choirmaster at St. Charles Borromeo and who died a year short of a century before Frans Moors chanced across the most valuable part of his heritage. So had Berlioz lied when he wrote of burning the work? Probably not, although his Memoirs do occasionally twist the truth to suit his purpose; more likely he had forgotten his gift of the score (not necessarily the only one, of course) to Bessems – and he could still have had a glorious bonfire with the parts.

It was John Eliot Gardiner – whose glorious recording of the work has just been released by Philips Classics (442137-2, remastered and reissued as 464688-2), with Donna Brown, Jean-Luc Viala and Gilles Cachemaille, the Orchestre Révolutionnaire et Romantique and the Monteverdi Choir – who had the cachet of the first performance in modern times. They began a European tour in Bremen on 3 October last year, taking in Vienna, Rome and other places before culminating in a televised performance in London's Westminster Cathedral nine days later, and it's that live performance which has now come out. France has always been tardy in acknowledging the stature of her greatest composer – nemo propheta in patria sua – and the first modern performance in France wasn't quite such up-market stuff. The honor had fallen (doubtless through musico-political manoeuvring of a suitably French nature) to the "Opéra d'Automne" Festival, located in the beautiful little fortified town of Semur-en-Auxois, in the rich wine-growing countryside of Burgundy. The performance took place inside one of France's most striking mediaeval monuments, the twelfth-century Romanesque Basilica of St. Madeleine at Vézelay, its bright interior now dazzling in the glare of TV arc lights. A couple of rows from the front, perched forward in anticipation, sat the slight figure of Frans Moors, a beam of entirely justified pride rarely far from his lips.

The contrast between Gardiner's disc and the lacklustre performance the Messe solennelle received in Vézelay underlines the strengths of this new recording. The Artistic Director of the Opéra d'Automne is Jean-Paul Penin, who like many young conductors has a position with an eastern European orchestra that can't afford a better-known name. Penin still has a lot to learn, and his orchestra, the National Philharmonic of Kraków, imported with its choir into France for the occasion, played raggedly and unconvincingly under his erratic direction. The choir, too, instead of being banked up to direct their contribution towards the audience, was positioned way down the vast apse, produced an unfocussed sound that disappeared into the cavernous depths of the Abbey. Gardiner's acoustic, Westminster Cathedral, might appear equally unfavourable, on the surface, Instead, Philips engineers have managed to exploit its size without sacrificing detail, and Berlioz's extraordinary vision comes across blazing with life.

The intensity of Gardiner's performance complements the acuity of ear of the twenty-year-old composer. To be sure, the Mass has debts to Cherubini, the biggest musical name in the Paris of the day, and to Berlioz's teacher, Jean-François Le Sueur; and there are occasional awkwardnesses that might be expected from such an inexperience writer. Yet the sheer individuality of his inspiration leaps from the score: he seems to have sprung, almost fully formed, from his own head. In spite of his later misgivings it's full of marvellously spontaneous invention – one of my favourite passages is the gorgeous Incarnatus Est, a blissfully simple duet for soprano and tenor. And repeated listenings have confirmed that the piece does hang together as a convincing whole: Berlioz at twenty, for all his lack of experience, had found his own voice and knew how to use it.

Once he had decided that the Messe Solennelle was no longer to be allowed out, Berlioz quarried it for material for decades – so it's a tune-spotter's paradise. The Kyrie which follows a brief orchestral introduction offers music that recurs in The Damnation of Faust, the Symphonie Fantastique and the Requiem. The Gloria contains thematic ideas that can be found in Benvenuto Cellini and the overture, Le Carnaval Romain, that he drew from that score. The melody that opens the Gratias is the backbone of the "Scène aux champs" from the Fantastique. The "Resurrexit" contains that awe-inspiring moment where, in the Requiem of 1837, the six timpanists make their shattering entry; here that tremendous crash is heard on a tam-tam, played at the first performance by Berlioz himself . The list could go on, underlining more and more firmly how, at this early age, Berlioz had already found his feet. His radicality was not acquired – it was an essential part of his musical language. What happened after the Messe Solennelle was a process of refinement, of further exploration and experiment.

Luckily, the re-discovery of the Messe Solennelle will not be solely a European privilege nor merely a recorded phenomenon. Bärenreiter, publishers of the complete Berlioz edition, have been laying plans for an extended series of performances throughout the world. Bärenreiter's Wolfgang Timaeus, sitting next to Frans Moors in Vézelay Abbey, had begun to reveal their plans ("We have a large number of performances planned across the globe – in France especially, of course, but also in Germany, Italy, North and South America, Japan…. There are a number of very prominent conductors involved: Seiji Ozawa and the Boston Symphony in North America and Japan, James Levine in Vienna with the Philharmonic…") when his voice was lost in the welter of applause that greeted the arrival of conductor and soloists, for the first hearing of Berlioz's Messe Solennelle in his native land for 158 years. Gardiner's audiences, scattered across Europe, fared much better, and his recording, which offers the added attraction of the revised version of the "Et Resurrexit" that Berlioz allowed to survive, will remain a central point of the Berlioz catalogue for decades.

Copyright © 1994-2010, Martin Anderson