Saint Paul would not be amused. In his book, women in church were best seen and not heard. So what he would make of a touring opera production designed to be performed in a series of four Irish churches, heaven only knows. Not just any opera, either, but one composed for the distinctly dodgy moral climate of the Venice carnival - and the opera's plot can be summed up in one saucy sentence: "lots of boys love girl, who turns out to be boy."
Or is that a fair description of Francesco Cavalli's comedy Erismena? "Absolutely," chorus Rodney Grant and Andrew McLellan, as we take a pew in the graceful, dark-panelled nave of St Werburgh's, in the heart of medieval Dublin. "This beautiful slave girl that everyone's fighting over falls in love with the warrior - who is, of course, actually a woman," McLellan adds, helpfully.
"Oh, there are far more twists than that," says Grant. "You have to keep your wits about you in this opera. For instance, when the guy turns out to be her brother. . ." "Ah, yes, the hint of incest," muses McLellan, the administrator of Opera Theatre Company. "And then there's the stock character of Venetian opera, the nurse, a kind of pantomime dame. So our tenor will be dressed as a woman the whole time. I'm not sure - is he keeping the beard?" Only if it's in the best possible taste, one assumes. But there's a real-life twist to this operatic production, the sort of twist which might have given even Cavalli and his famously inventive librettist, Aurelio Aureli, pause.
McLellan has been instrumental in this whole opera-in-a-church plan. And how did he know that St Werburgh's would be the perfect space in which to perform an opera? Because, he explains, as we wander around the marvellous gallery and gaze down at the ornate carved wooden pulpit, he used to be a curate here. "From 1997 to 1999," he says, "I was a curate at Christ Church, which is part of the same parish." The young curate was very taken with the building's graceful classical interior, and when a visiting gospel choir from Ohio inquired about a performance space, he decided to put on a concert at St Werburgh's; which in turn led to a series of concerts; which eventually led McLellan to leave the ministry and take an arts administration course at UCD.
He speaks lightly of the move - "I was doing arts administration anyway, so it made sense to do it full time" - but as he points out the church's most notable features, his affection for St Werburgh's, building and parish, is still palpable. "See the royal crest over there? That was the Viceroy's pew. And this gallery was really the place to be seen at church in Dublin on Sundays. Even now it's a small parish, but there's a great buzz about it. And the present rector is keen to have it recognised as part of Dublin's heritage - not just Dublin's Protestant heritage." There have been churches on this site, named after St Werburgh, since the 12th century.
But while the dignified interior and splendid acoustics may make a church seem like the ideal performance space, it has its drawbacks when it comes to designing a successful opera production. Which is where Rodney Grant comes in. He's in charge of set, costume and lighting design for OTC's Erismena and says he relishes the challenge of designing a show to fit not one, but four distinct churches full of character.
"First of all there's the light. You can't black out the church, so we'll start the first act in twilight - I like that." Compared to a Greek opera he once staged in a Tasmanian warehouse, St Werburgh's, with its high, unadorned windows, is a doddle: "That was probably the most difficult show I've done. It was a huge place on the docks, totally empty. We had to bring everything in."
Next challenge: all the seating must be on the same level. "It means we have to raise the stage to eye level, so everything's sort of chopped off," he says. "Except that it will be very high."
How high? He waves nonchalantly at the roof. "The main part of the set is a massive chair, which the king resides on. I said to Andrew Slater, the singer who is playing the part, 'you'll have to climb up a ladder that's about two metres high', and he said 'fine, whatever'. I wanted to cut off his train, just in case - but he insisted on keeping it."
From St Werbugh's, Erismena will move to Christ Church Cathedral in Waterford, the only neo-classical Georgian cathedral in Ireland, whose highly-praised interior has recently undergone extensive restoration. After that, it's on to St Nicholas's blue-grey limestone collegiate church in Galway; and the tour finishes at St George's on Belfast's High Street, described in a Papal Taxation Roll of 1306 as "the chapel of the Ford".
As for the look of the show itself, it will, says Grant, have "a very eastern flavour - it's set in Persia, so I went down that road, with a nod to the colour and exoticism of the Venice carnival. I had great fun measuring bricks and things at the British Museum, which has three rooms of Mesopotamian artefacts." The sound of the piece will be equally exotic, with a range of baroque instruments from the theorbo to the baroque harp being played by an ensemble of Irish period musicians conducted - from the harpsichord and organ - by David Adams.
But according to McLellan, it's the drama - and especially the twists and turns of that fiendish-plot - which makes Erismena such a delightful confection. Premiered in 1656, the piece was a huge box-office success in 17th-century Italy, and, he says, it's easy to see why. "We're talking, during this period, about the birth of opera as we know it. People tend to think of Monteverdi's Orfeo, in 1607, as the starting point - but that was really a private entertainment for the Dukes of Mantua, and Monteverdi was a kind of servant.
When he moved to Venice, there was this totally new phenomenon which began with the opening of public theatres in 1637, where an impresario had to provide entertainment to please a paying public. Venice at carnival time was the playground of the rich - there was a kind of mardi gras madness that went on." It should suit 21st-century Ireland right down to the ground.
Cavalli's Erismena is at St Werburgh's, Dublin, on September 15th and 16th; at Christ Church Cathedral, Waterford, on September 18th; St Nicholas's Church, Galway, on September 20th; and St George's Church, Belfast, on September 22nd. Details: 01-6794962.