The French pianist Yvonne Loriod, who has died aged 86, was for half a century the inspirer and accredited interpreter of the piano music of Olivier Messiaen, and for three decades his devoted wife. She was also a dedicated champion of the piano works of Pierre Boulez, André Jolivet, Jean Barraqué and Arnold Schoenberg, and an influential teacher.
Born in Houilles, on the north-western outskirts of Paris, she began to play at the age of six. Her father was a good improviser at the piano; her godmother, Madame Sivade, began to give her lessons when she was 11, and later prepared her for entry to the Paris Conservatoire. By the age of 14, Loriod had already learned the whole of Bach's Well-Tempered Clavier, all the Beethoven piano sonatas, the complete works of Chopin and Schumann and all the Mozart piano concertos.
At the Conservatoire she studied first with Lazare-Lévy for piano and André Bloch for harmony. When the Nazis deported both these teachers in the early months of the Occupation (during which she used to give recitals of music by "Bartholdy", the Nazis never realising this was the banned Mendelssohn), her piano studies resumed under Marcel Ciampi and her harmony ones under Messiaen, who returned from his prison camp to the Conservatoire in May 1941.
Messiaen was quick to recognise her extraordinary musical abilities, and in the early months of 1943 wrote his two-piano work Visions de l'Amen, in which he took creative account of her particular technical strengths, incorporating into her part, that for the first piano, "the rhythmic difficulties, the chord clusters, everything which is velocity, charm and sound quality", while reserving for himself "the principal melodic material, the thematic elements, everything which demands emotion and power". If this division of labour, together with what the composer referred to as Loriod's rôle de diamantation in the Trois Petites Liturgies de la Présence Divine, premiered two years later, suggests a traditionalist view of feminine pianism, Loriod's command of keyboard power was amply recognised in the solo cycle Vingt Regards sur l'Enfant-Jésus, which she premiered in the Salle Gaveau, Paris, on 26 March 1945.
From then on, she was the muse not only for his piano works but for most of his orchestral ones as well – as he said in late life, "I'm married to a great pianist and I always imagine her in the midst of the orchestra" – and when, in the late 1950s, Heinrich Strobel commissioned what would become Chronochromie, he felt obliged to specify, "This time, no ondes martenot and no piano!" Of the twelve orchestral works Messiaen wrote from Turangalîla (1946-48) onwards, no fewer than nine include a part for piano; the quasi-vocal swooping of the electronic ondes martenot was often executed by Loriod's sister Jeanne.
Loriod won no fewer than seven first prizes at the Conservatoire, including one for piano in the summer of 1943, and studied composition with Darius Milhaud until 1948. But by this time she had decided to become a pianist rather than a composer and started on her successful international career in that year. Although she played Mozart often, including a cycle of 22 of his piano concertos in Paris within five weeks in 1964, her reputation was made in contemporary music, much of which was almost or entirely unplayed by others - one suspects as much for technical as for aesthetic reasons. Other first performances, apart from those of Messiaen's works, included Boulez's Second Piano Sonata (1950) and Structures II at Donaueschingen with the composer at the other piano (1961), Barraqué's Piano Sonata (1957) and Jolivet's Second Piano Sonata (1959). She also made a number of pioneering recordings in this repertory.
After a spell teaching at the Staatliche Hochschule für Musik in Karlsruhe, she was appointed a professor of piano at the Paris Conservatoire in 1967, and remained there for a quarter of a century. Pierre-Laurent Aimard, Paul Crossley and Roger Muraro were among her pupils. She also gave masterclasses worldwide and was much in demand on juries, where her experience and total command of all things musical lent her a natural authority.
In 1959, Messiaen's first wife, the composer and violinist Claire Delbos, died, and Loriod gave the first performance of the Catalogue d'Oiseaux. She and the composer got married two years later and had a working honeymoon in Japan, from which sprang the orchestral work Sept Haîkaï. Messiaen moved in to her flat in the rue Marcadet and, as other apartments became vacant, they knocked through walls and installed 15cm-thick soundproofing. For these last 30 years of Messiaen's life, until his death in 1992, she acted as proofreader and musical factotum - making the vocal score of his opera Saint François d'Assise took two years. Expected visitors were assured of a warm welcome and, if they were British, of tea.
No doubt living with Messiaen, as with most geniuses, had its ups and downs, though the downs seem to have been very few. An unpublished letter of Darius Milhaud, written from Aspen, Colorado, says: "Les Messiaen sont ici. Comme toujours, charmants et impossibles." Given that Messiaen found the real world of timetables and electric plugs hard to crack, Loriod was called upon to be manager and travel agent as well as wife and interpreter. On his bird-listening trips she would be in charge of the tape recorder and would be expected to sleep in haystacks or barns in order to be up for the dawn chorus. Her demurrers at travelling to Bryce Canyon in Utah or New Caledonia ("wouldn't Assisi do?") went for nothing; although when it came to it, they both enjoyed these exotic trips enormously.
Loriod edited a number of her husband's posthumous works, notably the Concert à Quatre. When the definitive history of 20th-century music comes to be written, she will find an honoured place, not only as an exceptional pianist, but as one who, because her technique made possible for Messiaen what he called "the greatest eccentricities", had a profound and lasting effect on that music, both pianistic and orchestral. She is survived by her sister Jacqueline.