Like many composers in the late 20th century, he was open to all the possibilities of the century, and took advantage only of those which helped him write what he had to. His individual mixture of tonal and atonal material created a particular forward thrust in his music: harmonic tension was always present, and this, combined with a strong rhythmic impetus, kept not only the audience but also the players constantly involved.
Keuris was born in 1946, and as a teenager studied music in his home town of Amersfoort with Jan van Vlijmen. In 1963 he entered the Conservatoire in Utrecht, where his composition teacher was Ton de Leeuw, and he graduated with the Composition Prize in 1969.
He stayed on as a teacher after graduation, refining a musical language where tonality was important, although his training from both van Vlijmen and de Leeuw had been in the then prevalent serial tradition. Keuris always had his doubts about this: "It's not that I'm against atonality," he said once, "but I don't know how to build large-scale pieces with it."
So it is not surprising that his first important piece, the Sinfonia of 1972-74, was a profoundly tonal work. It won the Matthijs Vermuelen prize in 1975, and established Keuris's name on the international scene. Its example inspired many composers in the Netherlands, as did Keuris himself, with his continuing commitment to teaching: after his first stint at Utrecht, he taught at the Hilversum Conservatory, the Sweelinck Conservatory in Amsterdam, and at the time of his death was head of composition back in Utrecht. He loved teaching theory and analysis as much as composition.
After the success of the Sinfonia, Keuris was regularly in demand for commissions: the list includes the Houston Symphony Orchestra and the BBC. In 1991 he was chosen as the Dutch composer in "Arturo Toscanini", a multiple commission from the Orchestra Sinfonica dell'Emilia-Romagna, which presented new works from all the countries of the EU.
As he developed, his musical language became richer and deeper. Keuris was never dismissive of other styles, but knew the way he had chosen was right for him. He always believed that music must actively communicate, and convince the listeners emotionally. Just as he had not rejected tonality, neither did he reject conventional forms: in fact, he became more attached to them as time passed.
The Symphony in D, which he completed in 1995, is a culmination of this process: not only is its title provocative in its naming of a key, but its formal processes are much more concerned with the mainstream symphonic tradition.
Certainly, before his final short illness he felt he was at the height of his powers, and that he had found a way to communicate his musical thoughts in the fullest possible way. At the time of his death he was working on a song cycle based on the poems of Rilke, for the distinguished Dutch mezzo Jard van Nes - in 1990, he had written one of his most beautiful works, the Three Michelangelo Songs for her.
Keuris was only an intermittent visitor to Britain, latterly for the much delayed British premiere of his Concerto for Saxophone Quartet and Orchestra in 1994, but thanks to the healthy state of Dutch culture much of his music has appeared on LP and CD, most recently the Symphony in D and the Second Violin Concerto - still to receive its first public performance.
Tristan Keuris, composer: born Amersfoort, the Netherlands 3 October 1946; married (two children); died 15 December 1996.