THE ARTS: When he comes to Dublin next week the composer Gavin Bryars will perform sonnets translated by the poet, writes Michael Dervan

The piece that opens Gavin Bryars's concert at Christ Church in Dublin tomorrow week is one he wrote "sort of by mistake". It's a piece based on a medieval source, a lauda, or song of praise, that the composer came across when he was doing a dance performance with a US choreographer, Carolyn Carlson, at the Fenice Theatre in Venice.

"She put together a solo work lasting at that time about 45 minutes, which had three pieces of mine. But it started with an unaccompanied piece for solo soprano, a medieval lauda sung by the soprano who works with me, Anna Maria Friman." Friman will be known to audiences in Ireland through her performances here as a member of the Trio Mediaeval.

Bryars, who started his career as a jazz bassist in the 1960s, suggested that, with the spirit of the original in mind, he replace the lauda with one of his own, so that the music would have a greater consistency. "But Carolyn had got quite fond of the medieval version, so we didn't do that in the first performance. But I wrote one for her to hear, and by mistake - there were three laude on the first recording of the Trio Mediaeval - I actually wrote one which wasn't the one Carolyn was using."

Then, of course, he had to work on the correct one, after which he felt compelled to do the third, as there were three on the Trio Mediaeval CD. The number has since swelled to 25, and, he says, he's likely to end up doing about 50 or more.

"The material," he explains, "comes from a manuscript source in Cortona, in Italy, where there's a collection of these unaccompanied solo vocal pieces, which had the same kind of character: it was verse, chorus, verse, chorus - ABAB - and so on. They're all basically Marian texts, texts about the Virgin Mary, but they're not liturgical. They were sung by a band of people called the laudesi, who were sort of evangelical, in that they would sing outside churches in the 14th century in order to exhort people to come in. It was like a warm-up act."

All of Bryars's endeavours in this area have been written for Friman, even when he's used eight soprano voices (Friman and seven of her students at the University of York, in England) or 11 (the Trio Mediaeval with the same group of students). They're all in a style of simple, unaccompanied, unadorned, modal singing.

"In the original versions the chorus and the verse are the same every time; the words simply change. I make the music evolve a little bit more, but I respect the character of the originals. For example, in the word-setting, where they do two or three notes to a syllable, I'll do exactly the same thing in mine. Take the word amore. If I were going to put more than one note on a syllable there I'd probably go amo-o-o-re. But they often go amore-e-e, which is slightly odd. But I will do that against my instinct, because I'm actually respecting the structure of the original lauda.

"I found it a great exercise and a great test of compositional skill, really, to write something which has no adornment whatsoever. There are no accompaniments; I can't do rich orchestration, I can't do some clever harmonies. I can't do anything texturally or subtle with dynamics and contrasts. I have one voice and one voice alone. It's rather like, if you're Jackson Pollock, and you've splashed paint around all your life, and suddenly you've got a pencil and paper and that's all you've got, or ink and paper, where a mistake really sticks out a mile. I find it a great exercise. I do them very fast. If it takes me more than an hour and a half I start again; I just leave it. They're quite quick, rather like a Zen drawing in a way. I think about it and then I go for it."

Saturday week's concert includes four laude, one to open and close each half of the programme. The sources of the stimulation for the evening's music are nothing if not diverse. The North Shore was written in 1993 for viola and piano, for performance at a concert given in connection with an exhibition in Edinburgh by the English artist James Hugonin, who lives in northern England and has a studio that looks across to Lindisfarne.

The North Shore, says Bryars, is based on the image of being on the coast, looking north. "It had this sense of Glenn Gould, the idea of north, the sense also of the obsession of the polar explorer Capt Hatteras, in Jules Verne's series of stories, always obsessively going north, this idea of the north as an attraction.

"The image was of the cliff tops of St Hilda's abbey in Whitby, which, although it's on the east coast, at that point you're actually facing north, you're looking up the coast. I had an image of this rather austere environment. It's one of four pieces I wrote, each one of which was for solo instrument and either piano or orchestra, one for each of the cardinal points of the compass. The Green Ray [from 1991\], a saxophone concerto for John Harle, is for the west coast. The East Coast \ is for bass oboe and orchestra. The North Shore was for viola and piano, The South Downs \ for cello and piano. So I have these four pieces, each of which has a different character in terms of the austerity or warmth or whatever of the region."

The North Shore has been enlarged as an ensemble piece and as a piece for chamber orchestra, and it's the version for solo viola and ensemble that's coming to Dublin. The "richer and more romantic" South Downs features also in a larger version that includes bass clarinet and electric guitar.

The Adnan Songbook of 1996 is a setting of eight poems by the Lebanese writer Etel Adnan, whom Bryars got to know through working with her on one of the operas for Robert Wilson's ill-fated The Civil Wars project for the Los Angeles Olympics, in 1984. She is, says Bryars, "a wonderful, very wide-ranging author of poetry and novels, and also a painter".

The songbook is "a sort of portrait of my ensemble", he says. "It's probably one of my ideal combinations. The heart of the group is the low strings, two violas, cello, bass. Then two fine solo players - Roger Heaton on bass clarinet and E flat clarinet and James Woodrow on electric guitar and acoustic guitar - plus voice. There are only six players, but we have quite a number of permutations between them. The third song only has strings, the fifth has no guitar, the sixth has no bass. Everyone in the piece has solo moments, so it's a way of giving people material to play. I remember at one point having a deputy second viola touring with me. He was amazed: he'd never played second viola before and had lots of solos. He found it quite unnerving."

The remaining work in the programme is an extension of Bryars's ongoing series of madrigals, which he began in 1998, setting texts by Blake Morrison for a Lockerbie memorial concert. A good friend, Bill Cadman, was killed in the Lockerbie air crash, and the poetry for the new madrigals was commissioned by his family. The idea of writing madrigals was stimulated on a number of fronts. John Potter of the Hilliard Ensemble offered advice "about materials and research outside the English tradition, looking essentially at the Italian Renaissance madrigal, and about texts, too, and the form and the content that the text would have".

And when it turned out that the early Bryars madrigals had all been written on Mondays, he realised, as he puts it, that he was committed to doing a book for each day of the week.

The second book, written on Tuesdays, set Petrarch in Italian for six singers, three sopranos (Trio Mediaeval again) and three tenors (from the Hilliard Ensemble). The third, written on Wednesdays, set Petrarch as translated by John Millington Synge for soprano, tenor, bass and lute (the members of Red Byrd). He ran into the Synge translations by accident in the library of the University of Victoria, in Canada, "17 Petrarch sonnets in this beautiful Irish prose poetry".

"Synge viewed these as a kind of test for the language he was going touse in Deirdre Of The Sorrows. There's a lot of things in common between the two. Both were incomplete at the time of his death, and when Synge was working on the sonnets he was aware of his own impending death. There's a kind of poignancy in his setting. One of the poems starts: 'Life is slipping from me.' All 17 of the poems are about Laura [Petrarch's muse\] and death, none dealing with the earlier, more optimistic things. The language, I thought, was absolutely wonderful."

Bryars was commissioned by Huddersfield Contemporary Music Festival to set nine of the translations. He says: "When I was asked to do the Dublin concert I thought it would be appropriate to bring some of the Synge poetry back to Ireland. I decided I would make a set of eight, so all these which were for two singers or one I made into this set of Irish Madrigals, with the accompaniment of low strings, two violas, cello and bass, instead of lute."

Although the Synge is a new turn in terms of choosing texts to set to music, it also represents a return to a passion of Bryars's youth. "When I went to university, in Sheffield, aged 18, I was knocked out by the university library. I'd never seen that kind of collection of books, and I spent the whole of my first terms - when I should have been studying music, philosophy, French and English literature - reading Irish plays: Synge, O'Casey, Yeats, Wilde. I just sat in the library and read these things."

It sounds as if this first major Irish literary encounter in Bryars's music is not going to be the last.

• The Gavin Bryars Ensemble, with guest artist Iarla ÓLionáird, is at Christ Church, Dublin, on May 15th