Good Friday dawns and with it, for all Christians, comes a mood of melancholy and lamentation. No choral music yet composed achieves the heartfelt expression of Bach's majestic Passion settings, taken from the gospels of St Matthew and St John, writes Eileen Battersby

They are epic dramas, meditations, yet also narratives. Those privileged to gather this evening at the Church of St Thomas in Leipzig, where Bach served for 27 years, will share in a musical tradition - experiencing a performance of the St John Passion.

Far closer to home, in St Mary's Dominican Church, Pope's Quay, Cork, European Quartet Week, which opens on Easter Monday, is introduced with an inspired prologue - the RTÉ Vanbrugh Quartet tonight performs Haydn's string quartet version of his The Seven Last Words from the Cross.

For Keith Pascoe, second violinist, the occasion is important. In addition to performing "the intensely challenging" quartet, he says "it provides us with a rare opportunity to perform in a Catholic Church. With a few notable exceptions, we would normally be invited to play in Church of Ireland churches."

Cellist Christopher Marwood describes the work as "a powerful and awe-inspiring testament" and sees it as "the string quartet's great contribution to the Easter devotions".

It was originally commissioned in 1785 by the Canon of Cadiz Cathedral, who had asked Haydn to compose instrumental music to be performed between meditations on Christ's last seven words - the declamatory statements addressed to his father in heaven as he was dying - during a special Good Friday ceremony. It was a technical challenge, the composing of seven consecutive Adagios or sonatas, each lasting about 10 minutes and all consistent with the tone of the service.

As Haydn wrote: "Each time, at the end of the sermon, the orchestra would begin again and my composition had to be in keeping with the presentation."

Admittedly, Haydn was to miss his deadline by two years. The work was first performed in its initial orchestral form in Cadiz on Holy Thursday 1887, about a month after earlier performances in Vienna and Bonn. Even for Haydn, a composer with a huge output, it was a major achievement. It is certainly innovative, at times pre-empting Beethoven and even more eerily Schubert - but it is also, more importantly, an evocative, almost symphonic piece that succeeds in approaching the weight of choral expression through its long, slow passages.

This is interesting, because although Haydn produced so much orchestral and chamber music, it had often been suggested that his essential self lay in his sacred music. He wrote many Masses, cantatas and choruses, all beautiful, if never achieving the pathos, humanity and grandeur of Bach. Haydn's finest sacred music came late in his career, culminating in The Creation. Itself inspired by Handel's Israel in Egypt, it best summarises Haydn the man and the Haydn the composer. Above all he believed music should delight the listener: "the weary and the worn, or the man burdened with affairs, may enjoy a few moments of solace and refreshment."

That solace is to be found in this unique quartet, which moves and transfixes, until the final, jarring, melodramatic earthquake sequence which does seem out of character. "What has happened? Is it death and damnation?" agrees Pascoe.

Perhaps it is intended as a way of stirring the living onward? Even so, it is remarkable that a quartet can seem to be speaking to the listener. There is a vocal quality. Just as it previews the visions of Beethoven and Schubert, there is also an unexpected but compelling sense of Brahms' much later Ein Deutsches Requiem (1869).

Working on The Last Seven Words From the Cross enabled Haydn, the most practical and businesslike of composers, to openly respond to its spiritual dimension. About 1800, he would look back and recall in the form of a note written for the later choral version, the circumstances that shaped his approach to this work, which was very important to him: having composed it, he worked a further three versions of it. It also remains unique in his oeuvre.

"It was some 15 years ago that I was requested by the Canon in Cadix to write instrumental music on the seven words of Jesus on the cross. Every year during Lent it was the custom in the cathedral in Cadix to perform an oratorio, for the greater effect of which the following arrangements were to contribute more than a little. The walls, windows and columns of the church, namely, were draped with black cloth, and only one large lamp hanging in the middle brought light into the holy darkness. At the noon hour all of the doors were closed: then the music began. After an appropriate prelude, the bishop mounted the pulpit, pronounced one of the seven words and then reflected on it. As soon as this was ended, he came down from the pulpit and fell on his knees before the altar. This pause was filled by music. The bishop mounted and left the pulpit for the second, third time etc, and each time the orchestra started playing at the end of his comments."

Haydn rarely wrote at length about any of his work, but this was an exception. And he was well aware of this. He was also a composer whose fame in his lifetime rested almost exclusively on publishing, not performances. He travelled little aside from his two successful visits to London, the first of which was undertaken when he was approaching the age of 60.

Assessing any of his pieces invariably leads to the ongoing debate as to whether Haydn was destined to be overshadowed by the mercurial Mozart, who was 24 years his junior and took up both the symphony and string quartet - forms which Haydn had diligently pioneered with an at-times folksy doggedness - and appeared to perfect them through sheer musical sophistication. Perhaps therein lies an essential distinction: whereas Haydn was experimental within the confines of the tradition to which he belonged, Mozart's genius was obsessed with symmetrical perfection.

Added to this, of course, is that Mozart's operas outclassed those of the older composer who had written about 20, 15 of which survive. Haydn's career was long; he would also outlive Mozart by almost two decades and remained active until about seven years before his death in 1809. Born in 1732 to humble but normal circumstances, he suffered none of the musical prodigy pressures placed on Mozart. Haydn's father was a cartwright with a liking for music, and the young Haydn could sing well enough to be dispatched to a Vienna choir school at the age of eight. He was 18 when Bach died, so Haydn, the father of the symphony (of which he composed 104), was in fact a child of the Baroque.

Despite his image as an establishment figure, the "Papa Joe" of the Viennese music world secure in royal patronage, he was a musical revolutionary, a radical classical innovator capable of balancing his market with the aesthetic. He would count the young, if ungrateful, Beethoven among his students. It is Haydn who is generally credited with the invention of the string quartet form, although some scholars dispute this, pointing to the work of the Italian master, Luigi Boccherini.

This debate aside, Haydn certainly pioneered the form, composing more than 90 quartets to Mozart's 23. Interestingly while Haydn was aware that Mozart was considered to have perfected the form, the younger genius always admitted that for him the quartet was the most difficult compositional medium.

Only a musical innovator, or perhaps a shrewd reader of the market, could have taken what was an orchestral work and scale it down to the dramatic and demanding quartet of tonight's performance. "There was always a need for new music," says Pascoe, "particularly in the royal courts who would want to show off the latest hits from their in-house composer, and the quartet was the ideal mobile vehicle for showing off a composer's latest work, as it meant you didn't need to bring an entire orchestra along."

Having also reworked the piece for harpsichord or pianoforte, Haydn devised in 1791 a fourth arrangement, the one most suited to its unnervingly vocal eloquence, a vocal version for soloists, chorus and orchestra.

The RTÉ Vanbrugh, artist in residence at University College Cork, continues to balance world-class performance with enthusiasm. Founded in 1986, it has already amassed an impressive discography, ranging from Haydn, Boccherini Quintets, Schubert, Dvorak, Beethoven's Complete String Quartets, an exciting Copland CD, and Stanford's Quartets 1 &2, as well as work by contemporary Irish composers such as Raymond Deane.

How is the quartet approaching this particular piece? According to Pascoe, the piece is "a kind of hybrid", and he says the orchestral nature of the music is noticeable. "What is very special is Haydn's use of continuous simple quaver passages, as if seeking a melody - they give the impression of missing voice. It achieves a sense of suspended animation and provides a mental space for meditation."

Playing seven slow movements must be exhausting. "Trying to get the scope of the piece is the biggest challenge," says Pascoe. Usually in classical music there is the fast-slow-fast scheme, "but here there are nine movements and eight of them are slow. Having spent the previous movements playing very slow, extended passages, you suddenly have the earthquake sequence and then you're there, having to play like the clappers. There is no doubt it is a great piece."

European Quartet Week could well be the highlight of Cork 2005.

The RTÉ Vanbrugh String Quartet performs The Seven Last Words from the Cross tonight in St Mary's Dominican Church, Cork. See today's Ticket for more details of Cork's European Quartet Week