The Pipeworks organ festival begins tonight with Rossini's final work, a playful bid for paradise, writes Eileen Battersby

Bringing an element of surprise to the proceedings is part of the fun for the organisers of Pipeworks, a festival that engagingly celebrates the exciting, diverse and often majestic organ repertoire.

Established in 1980, Pipeworks has settled into a three-year cycle, incorporating the Dublin International Organ Competition and making fine use of Dublin's Christ Church and St Patrick's cathedrals as well as St Audeon's Church, and St Patrick's Cathedral, Dundalk. The 2005 festival opens in grand style today, Bloomsday, with a performance James Joyce, with his love of voice, would have enjoyed: Rossini's Petite Messe Solennelle, performed in the chamber setting of the Shaw Room at the National Gallery in Dublin.

Few pieces of music achieve the unexpected quite as dramatically, and jauntily, as Rossini's maverick delight, which is neither little nor particularly solemn and is longer than most masses. Humour and playfulness, as well as a flair for theatricality, are integral to the art of Gioacchino Rossini, who believed that sacred music need not be removed from the secular.

Born to musicians in Pesaro, a town on the Adriatic, on leap-year day in 1792, Rossini, the master of the catchy tune, was the son of a trumpeter and a singer. He studied music in Bologna, and was to inaugurate what was to become the story of Italian music in the 19th century - opera as musical drama. In his career, begun in 1810 with a one-act comic opera, he wrote more than 30 operas, establishing a tradition which would be consolidated by Bellini and Donizetti and, ultimately, Verdi.

For colour, melody, energy, output and sheer entertainment, Rossini could be considered the musical equivalent of Charles Dickens. After The Barber of Seville, which premiered in 1816, Beethoven joined in the approval that greeted what would become the most popular comic opera of all. In 1824, Rossini moved to Paris, where he settled, becoming an honorary Parisian (in demeanour at least) and working on his epic William Tell, based on Schiller's play. Rossini's rousing celebration of Switzerland's folk hero was the composer's last opera, completed in 1829 when he was aged only 37. It lasts almost five hours and is rarely performed, yet it is a masterpiece and its large-scale coherence paved the way for Verdi.

Rossini retired from opera; he was rich, famous, revered, and happier than most. Pictures depict a portly entrepreneur complete with cane. Yet two unexpected late treasures would occupy Rossini's final years.

The first was his magnificent Stabat Mater which he wrote reluctantly, conscious of the austere beauty of Pergolesi's masterly 1736 setting. After a chaotic compositional history, partly occasioned by his lumbago, which made him dependent on some furtive co-writing, Rossini scrapped his 1832 version and composed a further four sections to add to his initial six movements, thus completing his final complete version in 1842. More lyric opera in liturgical attire than formal devotional piece, it has been described his last work. But it wasn't.

Some five years before his death in 1868, Rossini - ever the joker - set out to complete what he referred to as "the last mortal sin of my old age". The work itself was no idle joke. Rossini wrote a most deliberate piece, scored for eight opera singers and four soloists, "men, women and castrati", with two pianos and harmonium. The harmonium, or orgue expressif, brought its own individual sound to the music of the 1860s, and it is this quality which most excites Pipeworks music director Mark Duley about tonight's performance, which features the National Chamber Choir conducted by Celso Antunes.

"We will be playing the work as Rossini intended, as a small chamber piece, not the usual big treatment it usually receives, which all go perfectly well, but we will be following Rossini's original directions," Duley says. For him, it is a matter of colour and tone in a piece which balances histrionic religious fervour and the operatic tradition. The dry, rather brittle sound of the two 1840s grand pianos, one of which was once owned by pianist/composer Clara Schumann, will contrast with the unique sound of the harmonium.

For all its drama and moments of reverence, the Mass is a jaunty piece. In a note addressed to God, written on the manuscript, Rossini wrote: "So here it is, then, this poor little Mass. Have I written truly sacred music, or just damned bad music? I was born for opera buffa, as you well know. Not much skill, but quite a bit of feeling . . ." The composer concluded with the request: "Grant me a place in Paradise."

First performed for a private celebration, the consecration of a chapel in Paris, on March 14th 1864, the Mass in its 14 parts had a public performance the following day, and delighted the congregation, including the papal nuncio, as well as several music critics. Its popularity quickly led to its being transcribed for a full orchestra. Rossini obliged but did not want it played in his lifetime.

Instinct told him that a larger treatment could diminish the charm and intimacy of the original. Rossini intended his Petite Messe Solennelle as a final testimony to how well he could write for the voice. Tonight's performance will honour that legacy.