But the unusual thing about this particular script is that there are hundreds, perhaps thousands, of others who would back every word of it, including the claim to saintliness. As yet there are no reported miracles, but Tante Yvonne has letters from the terminally ill affirming how her husband's work eased their anxiety. She has stories of schoolchildren sitting their exams with her husband's photo in their pocket. "People feel his presence", she says. "His faith was contagious." And his grandeur is hardly deniable. Olivier Messiaen ranked among the great composers of modern times and, in his final years, was by common consent the greatest composer alive. Tante Yvonne herself is a woman of no small achievement - as the legendary French pianist Yvonne Loriod, and one of the chief interpreters of Messiaen's music. All of which is hard to reconcile with this extremely modest flat on the wrong side of Montmartre: three small rooms with not much of a view and the sole extravagance of sound- proofed walls - which, judging by the dull thump of a neighbouring stereo, aren't too effective. In fact, the Messiaens owned a couple of other rooms in the same block (it used to be a hotel) for storage and working space, and also had a summer house outside Grenoble which Madame Messiaen plans to turn into a museum. But the compact space in which I sit was none the less their home from 1962, when they married until 1992, when Messiaen died. Even in Soviet Russia, great men lived more ostentatiously.
Of course, you only have to see photographs of Messiaen - usually in a beret, with his shirt collar opened out over the collar of his jacket, 1940s peasant style - to know that he didn't live for show. If he lived for anything, it was God. The spiritual dimension to his work was constant, through a catalogue of scores that may not always be specifically "religious", still less liturgical, but declare a commitment to Christianity that stands alongside the 20th century's most significant statements of faith. It's tempting to call him a servant of the church, like JS Bach, and that's true insofar as he spent almost every Sunday of his adult life playing the organ at the great Parisian basilica of Ste-Trinite. But Messiaen's spirituality was more personal and contemplative than institutional and missionary. And the sound world of his music tends accordingly toward mystical reflection: a private and not always orthodox response to the Catholic faith that inspired it.
IN TRUTH, little about Messiaen was ever orthodox. He possessed one of the truly original minds of modern music: instantly recognisable, and not least because his "voice" as a composer hardly changed from the early keyboard scores of the 1930s to the last orchestral epic Eclairs sur l'au dela in 1991. Priorities and details shifted but the basic manner of expression, and the resulting sound, did not. And that's essentially because Messiaen systematised his compositional techniques into something that became like a set of self-imposed rules. There were rules of harmony which he derived from personal adaptation of modal scales; rules of rhythm, similarly adapted from Eastern sources. And, with time, there came to be two other critical ingredients. One was Messiaen's synaesthetic ability to relate sound to colour: in other words, he could play with a prism (one stands prominently on display inside the Paris flat), take inspiration from the interaction of tones, and turn it into music which - for him - would be a clear and unfanciful matter of blue turning into yellow and, by bar 62, set against a streak of orange. It was like composing in stained glass, and produced luminous textures that somehow survive in performance, regardless of whether the interpreter or his listeners "hear" colours in the same way.
The other key ingredient in Messiaen's work was birdsong, which he would notate on country walks - Madame Messaien beside him with a tape recorder - and turn into melodic or rhythmic material for incorporation into scores like the Catalogues d'oiseaux for piano (1958) and Oiseaux Exotiques for piano and ensemble (1956). It comes, more often than not, without developmental linkage. The birdsong just takes its place in a parade of found objects (a snatch of plainchant, a tone-cluster, a number- game) laid out like precious items on a nursery school study-table and with much the same degree of innocence, however subtle the theological, structural and symbolic agendas that support it. And that innocence in Messiaen's work is both its pleasure and its problem. For all its systematic principles, the outcome can seem random, static, improvised and sometimes downright vulgar - as in Messiaen's best-known work, the blowsily exuberant Turangalila symphony of 1948.
An example of the sensuality that coexisted with surprising ease beside Messiaen's spirit-led asceticism, Turangalila is a great romp of love: peculiarly gallic and bizarrely passionate for a beret-wearing bird- watcher in outsized collars. I hardly dared ask Tante Yvonne if, in the privacy of their little flat, the saintly Messiaen was a man of passion. But I did. And the answer was yes, although it was, in her oblique words, "the joyous passion of a man who has known suffering".
Messiaen's suffering in the Second World War we know about. Incarcerated as a PoW in a German prison camp, he left a lasting testimony to the experience in another famous score: the Quartet for the End of Time, written for performance on whatever instruments were available in the Stalag, and first performed to an audience of 5,000 inmates, no doubt largely uncomprehending but apparently appreciative. But Messiaen's post-war suffering was a more private matter; and closely involved Yvonne Loriod herself. They met in 1942, when Messiaen was teaching what proved to be a celebrated class in musical analysis at the Paris Conservatoire. "He had only 12 official pupils," Loriod remembers. "But there were far more than that, musicians from all over the world, who would turn up just to hear him. I was one of the pupils and played musical examples for his class on the piano. He was my maitre; and he always remained so, even when we were married. I never called him by his first name, it was always "Messiaen". Or "maitre". I'd have never thought to call him "my Olivier". Never. I admired him too much to do that."
Yvonne Loriod became Messiaen's muse, and the reason why so much of his output is for piano or, at least, with a prominent piano role. Everything from 1943 was written for her, including the Vingt regards sur l'enfant Jesus (1944) and all the bird pieces. To this day, at the age of 74, she plays them in concert - as she will next weekend at the Barbican, when she takes the piano solo in Turangalila. But when Messiaen and Loriod first fell in love, back in the 1940s, there was a problem. Messiaen was married. It was a tragic marriage, to a woman with a debilitating mental illness that left her incapable. But as a good Catholic, Messiaen could neither divorce her nor give physical expression to his feelings for Loriod. "So we cried", says Loriod. "We cried for 20 years until she died and we could marry."
The wait was a testament to patience: a quality manifest not only in the long durations of Messian's music but in just about every other aspect of the composer's life - including those 60 years as organist at the Trinite where every Sunday Messiaen climbed the winding stair up to the organ loft to play for the 11.30am mass. It became a cult event, with a fair proportion of the congregation there for no other reason than to witness the maitre in the loft; and for anyone who wants a closer understanding of the maitre's world, a visit to the Trinite is still core curriculum.
THE ORGAN in general and the organ of the Trinite in particular - a great French Romantic beast of a Cavaille-Coll - was central to Messiaen's output, inspiring a catalogue of monumental scores, from Le Banquet Celeste (1928) to the two-hour long Livre du Saint-Sacrament (1984), that were the spinal cord of his creativity. That they sound so freely "improvised" in performance (despite the specific way that Messiaen notates them) is no surprise when you go to the 11.30am mass and find that the sole function of the organist titulaire (now Naji Hakim, Messiaen's immediate successor) is to improvise. The Trinite's tradition is Catholic charismatic, and what little there is in the way of liturgy and choral singing is accompanied by an assistant organist in the body of the church. High up in the West-end loft, the titulaire comes out like a recitalist, to improvise at the begining, at the Offertory and the Dismissal. That's the job, and it explains a lot - including why the saintly Messiaen never wrote a single choral setting of the Latin liturgy.
In the old days, Yvonne Loriod was always there beside him, taping what he improvised. One of her tasks in widowhood is to sort a cupboardful of the recordings into some kind of archive - although work on that won't start until she's finished editing the last few of Messiaen's compositional treatises to be published. She sees herself as the necessary custodian of such things, since Messaien's son (by his first marriage) takes no interest. "He doesn't understand his father's work", she says. "He doesn't get involved." Nor, evidently, does he get involved with his stepmother, and I can't help asking if she gets lonely in that little, ordered flat without a view. "Of course", she says, "but when I need Messiaen he's still there. Since he died, I've been attacked twice in the street by muggers, and both times he has protected me. Without a doubt.
"And then, I'm busy. There is much to do, with concerts, the museum, organising Messiaen's memorial sculpture. It's a bird, with a quotation from Harawi (one of Messiaen's love-scores) on its breast. It will be beautiful, I think."
Yvonne Loriod, BBC/Barbican Messiaen festival: Barbican, EC2 (0171 638 8891), Saturday & Sunday 16 January.Reuse content