The music and performances are original and workmanlike: usefully uneasy and edgy. New this year on the label is Harle’s Silencium: Songs of the Spirit. The words are Harle’s own, and a fine concoction of twaddle some of them are. Never mind, this is superior pop from the vaults.The path through the cloister is well worn. It demonstrates that lucky radio play can be as powerful as stunts. In 1981, Ted Perry, the boss of a fledgeling record company, Hyperion, tuned in as usual to an early music show on Radio 3. “I suddenly heard this serene and beautiful music and waited for the announcement.

It was called “A feather on the breath of god”, and was music written by the 12th century Abbess, Hildegard of Bingen. By chance the Cambridge medieval literature and music don, Christopher Page, whose Gothic Voices group had been formed to perform the music of Hildegard, was on the telephone about another Hyperion record soon after and Perry decided that he must recreate the broadcast on disc “It was one of the simplest things I’ve ever done It was recorded in a day” A couple of plugs on radio, and an enduring hit was born. Three hundred thousand units later, and rising, Perry says: “Hildegard pays for my mistakes. Of course it has Emma Kirkby on it, and she’s a cult performer.There’s a strong feminist slant: a lesbian bookship in Texas sells a thousand a year. Hildegard remains a star with her chants for the feast of St Ursula, Eleven Thousand Virgins (repeating a medieval exageration of the number who were martyred with Ursula sooner than marry). This is set to be big for the American women of the Anonymous Four and their label, Harmonia Mundi. They are the “Fab Four of Medieval music”, according to the New York Times.

Demurely clothed, they scored well with their stark but sweet account of Medieval Hungarian Music, A Star in the East in 1996 and the virgins will surely triumph too.In 1994, it was an elderly Spanish record of some mostly elderly Spanish monks of the Benedictine community of Santo Domingo de Silos, chanting the Gregorian plainsong, which brought EMI a huge seller. “The performance was really pretty ordinary”, says James Jolly, editor of Gramophone magazine. “When you compare them with a modern polyphonic group like the Tallis Scholars, they’re pretty rough”. The Tallis Scholars were the first to take the genre to the very top, winning the magazine’s record of the year in 1987, with two 15th century masses. “But”, says Jolly, “Perfection is not the whole point when you’re listening to monks for whom this is their whole work, the core of their spirituality”.In 1994, EMI also had Ikos, which combined Henryk Grecki, Arvo Part and John Tavener, three of the heaviest hitters in the genre. But Steve Sanderson of ECM New Series (distributed by New Note in the UK) was in charge of the UK marketing of the best combination of critical and commercial success. This was Officium, in which the Norwegian Jan Garbarek blows saxophone (Harle-style) across medieval plainsong – some of it Perotin’s – sung by the Hilliard Ensemble.

There’s never been a follow-up to this triumph, though its creators do give concerts, as they did on December 5 at the Barbican. Sanderson promoted the record first with a live concert in King’s College Chapel in June 1994 That autumn Radio 4’s Kaleidoscope featured it. Sanderson recalls: “Hundreds of people called up that very day. The classical press took to it, and Q [the cult rock magazine] devoted a whole page to it. We expected to do well, frankly, and initially shipped about 10,000 copies”. In the UK the record sold over 80,000 and half a million round the world.Officium is lovely: smokey, modern, jazz improvisation paying homage to incense-fumigated, ancient, discipline The sax, most agree, becomes another voice. I always see it as a drift of cigarette smoke, sacrilegous and delicious, in the choirstalls There are dissenters.