The bards would hardly recognise a modern harp. Their beloved metal-strung instrument was far more distinctive, writes Mary Phelan

It is our national symbol and part of what we are. It graces our coinage, is the emblem of our favourite tipple. It is seen as being as Irish as red hair and freckles or good humoured loquaciousness. Yet it is based on a misconception.

Take a good look at the instrument at the centre of our coins and our august musical heritage. Does it really look the same as that played from Bunratty to Belfast? Is it not somewhat fatter, rounder and smaller than its contemporary manifestation? Of course the crucial thing about instruments is what they sound like rather than look like. Were you to hear the Brian Boru harp - or the Trinity harp, as Siobhán Armstrong, director of Scoil an Chláirsigh, the first Irish Summer School of Wire-Strung Harp, more correctly calls it - you would discover that it sounded nothing like the dulcet tones we associate with Mary O'Hara, Kathleen Watkins or even the more spunky contemporary playing of Laoise Kelly or Michael Rooney.

The modern Irish harp is a mutated descendent of the instrument loved by the bards. The ancient Irish harp was strung with metal, giving it a distinctive bell-like sound. Its notes rang out clearly and with an extremely long sustain - very atmospheric for bardic declamation but potentially problematic nowadays.

The modern - or, as purists would have it, neo-Irish - harp is a child of the 19th century, modelled on the classical harp and strung with gut or nylon. It also has a very different sound. Its courtly antecedent is played using the fingernails, which have to be grown for the purpose. Hand position, technique and ornamentation all differ from those for the gut- or nylon-strung instruments we are now familiar with.

This evolution is closely tied up with our history, both political and musical. Although central to the highly structured old Gaelic order, by the end of the 18th century the harp had well nigh disappeared from Irish life. The Belfast Harp Festival of 1792, at which the young Edward Bunting transcribed the harpists' music, preserving it for posterity, mustered a mere 11 players, all of them elderly. It was the end of an era.

A century later the ladies of the parlour reintroduced the harp to Ireland. This time it was the ethos of the drawing room rather than the chieftain's court that provided the instrument with its context. The repertoire reflected this. Moore's Irish Melodies replaced planxties, reels and laments. No longer a clearly defined profession, harp-playing was feminised.

The more recent revival of the instrument's fortunes was precipitated largely by the Japanese company Aoyama, which began mass-producing "Irish harps" during the mid-20th century. These were strung with gut or nylon and played with the finger pads, unlike the original wire-strung instrument.

As has been the case before, the impetus for the revival has come largely from the US. Although the wire-strung harp has found a niche there over the past half-century, very few played it here. In fact most people have never heard of it.

There have, of course, been some notable exceptions. The indomitable Gráinne Yeats was an early proponent. The late Derek Bell, Renaissance man of Irish music, had a wire-strung harp among his eclectic collection of instruments and occasionally used it in recording.

Paul Dooley busked regularly on Grafton Street playing a wire-strung harp during the late 1980s and can still be heard at the Cliffs of Moher during the tourist season. Inspired by the playing of Alain Stivell, who also used his fingernails, he stumbled on wire strings by default rather than design. Self-taught and using guitar strings on the instrument he had built at home, he discovered only belatedly that he was doing things differently from other harpers.

Siobhán Armstrong is determined to rescue the instrument from obscurity. A specialist in medieval music, she too cut her musical teeth on the modern Irish harp, studying under Nancy Calthorpe at the College of Music in Dublin.

A growing fascination with baroque instruments led to her finally discovering the wire-strung harp. "I had amassed a collection of historical harps," she says, "and yet I wasn't aware of the wire-strung harp. It was like the missing link. Once I encountered it there was no turning back." Although she still performs abroad regularly with early-music ensembles such as Les Arts Florissants, the mission to revive the fortunes of the cláirseach has become central to Armstrong's life. She set up the Historical Harp Society of Ireland last year and has begun teaching the instrument in Kilkenny. Organising a summer school in the city was a logical next step. "This new summer school is part of a concerted effort by the society to bring about a revival of the playing of our magnificent national instrument," says Armstrong, whose gold-stringed, superbly toned replica of the historical harp featured strongly at the summer school.

Making a rare appearance in Ireland was Ann Heymann, a US virtuoso player who has championed the wire-strung harp for three decades. As well as teaching at the summer school Heymann performed at a gala concert last night.

Armstrong has been delighted by the response to the event. "At first I was a bit apprehensive about numbers. But we have students from as far abroad as Hungary and Italy. Most importantly, we have six very enthusiastic Irish students. That is really heartening." Building on the summer school's success, plans are already under way for follow-up events over the winter.

The summer school is due to end tonight with a final student concert