Karl Jenkins

The short answer to the question most often asked about him is yes: he is a classical composer, in the sense that his best known works are written for chorus and orchestra and are performed by choral societies, cathedral choirs and symphony orchestras. He arrived at that repertoire by an unusual route, through jazz and rock and then through music written for advertising, and the route is part of the explanation for how the music sounds.

Penclawdd, the oboe and the jazz years

Jenkins trained first as an instrumentalist. He learned the oboe, played in the National Youth Orchestra of Wales, read music at Cardiff University and went on to postgraduate study at the Royal Academy of Music in London. The oboe is worth noticing, because it is a solo instrument with a narrow, penetrating sound and a player who spends a career making reeds and listening to a single line. Composers who begin as oboists tend to write melodies that a single voice can carry.

He then moved sideways into jazz, taking up the baritone saxophone and the keyboards, and joined Nucleus, the jazz rock group formed by the trumpeter Ian Carr, which won first prize at the Montreux Jazz Festival in 1970. From there he joined Soft Machine, one of the central bands of the Canterbury scene, and remained with the group through the 1970s, becoming its principal writer. That decade taught him the ostinato: a short pattern repeated under a slowly changing surface, which is a rock and jazz habit rather than a symphonic one, and which runs through almost everything he has written since.

Advertising music, and what it teaches

Through the 1980s and into the 1990s Jenkins wrote music for television commercials, an industry that pays well and imposes a discipline most concert composers never face: state the idea in the first two seconds, make it memorable on one hearing, and finish inside thirty. Several of the themes that later grew into concert works began there. The material that became Adiemus was first heard as the music for an airline campaign, and the wide public recognition that followed is what made the album possible rather than the other way round.

What Adiemus actually is

Adiemus is not a work in a language. The syllables the choir sings were invented by the composer and chosen for their vowel colour and their consonant attack, so that the voices function as an instrumental section rather than as a vehicle for a text. There is no translation, because there is nothing to translate. The word Adiemus itself is a coinage that resembles Latin without being it.

The first album, Adiemus: Songs of Sanctuary, appeared in 1995 and was followed by further Adiemus volumes. The scoring is characteristic: a female voice or a small group of voices over strings and a large percussion battery, with the melody harmonised simply and the pulse kept steady. Listeners who expect a choral work in the cathedral tradition are usually surprised by how little counterpoint there is. The interest sits in colour, in the percussion writing and in the repetition, not in the interweaving of independent lines.

The Armed Man, and why it is programmed so often

The Armed Man: A Mass for Peace, completed in 2000, was commissioned by the Royal Armouries and is dedicated to the victims of the conflict in Kosovo. Its spine is the ordinary of the Mass, the Kyrie, Sanctus, Agnus Dei and Benedictus, interleaved with texts drawn from several traditions and periods, so that liturgy and non-liturgical writing alternate. The title comes from L'homme armé, the fifteenth-century secular song that Renaissance composers repeatedly used as the basis for Mass settings, which places the work inside a very old practice even where its idiom is modern.

Four practical facts explain why amateur choirs programme it more than almost any other choral work written since 1980. It runs about an hour, which fills a concert on its own. It is written for a standard four-part chorus and does not demand professional voices, though it does demand stamina. It can be performed with a full orchestra or with reduced forces, so a choral society can match the piece to the money it has. And its subject, war and its cost, gives a promoter an obvious occasion, which is why it appears so frequently around Remembrance. The Benedictus, with its cello solo, is regularly performed on its own.

Stabat Mater and the later works

Stabat Mater, first performed in 2008, sets the medieval Latin sequence on the mother of Christ at the cross, but adds texts in other languages and brings Middle Eastern instruments and a Middle Eastern vocal line into the orchestra. It is the clearest example of a habit that runs across his output: taking a fixed liturgical or ceremonial frame and filling it with material from outside the European tradition. Later works include The Peacemakers, Cantata Memoria for the children of Aberfan, and a series of concertos and instrumental pieces. He was knighted in 2015.

Where he sits in the Welsh line

Jenkins does not write in the manner of Grace Williams, Alun Hoddinott or William Mathias, and he is not usually discussed alongside them by people who follow the Welsh symphonic tradition. What he shares with them is the country's choral base. Wales has spent nearly two centuries producing amateur singers in quantity, and the composer whose music those singers can actually perform will be heard far more often than the composer whose symphony needs a professional orchestra and a subsidy. That is a fact about supply, not a judgement about quality, and it accounts for a good deal of the distance between his performance figures and everybody else's.

Also in this programme

• Welsh classical musicThe composers, the choirs and the institutions
• Hen Wlad Fy Nhadau: Land of My FathersThe anthem, its author and its music
• The eisteddfodWhat an eisteddfod is, and how the music competition works
• Famous orchestral conductorsThe conductors most people can name, and why