Some people have misgivings about adaptations, but playwrights have always been inspired by the works of their predecessors, just as my play, ‘Christ Deliver Us!’, which draws on my growing up in 1950s Ireland, is deeply indebted to Wedekind’s ‘Spring Awakening’

SOME PEOPLE ARE bothered by adaptations. They say: what’s wrong with the original? Why make changes to it? Indeed, where do you get the authority to do so?

The first thing to be said about an adaptation is that, no matter how faithful it may be to the original, it and the original are always two very different, distinct works, sometimes profoundly so. A second point worth making is that the history of European theatre, like that of other performing arts, such as music, both orchestral and operatic, is a history of adaptation. Starting with Greek theatre and down to our own times there has been this endless process of adaptation, variation, imitation and recycling of other material.

I don’t know why this should be so. Maybe it’s because of the nature of performance – itself an imitative art. At any rate, playwrights have always been inspired by the plays of other playwrights almost as much as they are by the bits and scraps of experience upon which an original work is imagined into existence. Writers are, first of all, great readers. They inhale other writers’ works, sometimes without even knowing it.

Translation is a very different activity, although when you have playwrights who are also translators with a good knowledge of the language, you often get versions of the original plays that are both accurate and somehow infused with the imagination of the translator. I sometimes think this is the ideal kind of adaptation.

Indeed there is a scale of adaptation. At one end of the scale is the adaptation that is nearly (but not quite) a literal reproduction of the original. At the other end of the scale is the adaptation that has departed so far from the original that the first play has become a mere shadow behind the new one. When the imitation has been subconscious, the echo of the original is like a half-heard notation in the air.

What about language? What about producing a version of another play from a language different to one’s own, indeed from a language in which one may have no particular competence?

Most adaptors know the work they are dealing with in the first place from the experience of seeing productions in the theatre, sometimes many different productions. This was my own experience of Wedekind's Spring Awakening, although I missed the recent Broadway rock-musical version. In other words, the play is in the imagination, not as a printed text, but as a theatrical action on a stage. The question of language comes second to the stage experience. That said, there is now an accepted code of practice in theatre where an adaptor will work with a literal translation of the original, usually specially commissioned by the theatre.

There is one area of adaptation, however that does bear heavily upon the question of language. This is finding a local idiom that will be natural in the voice of the local actor. I remember debates on this issue in Field Day where we commissioned poets and playwrights to produce versions of classic plays especially for our own actors.

Part of the modern agitation about adaptation is due to the mystique of originality. We now put a very high price on the degree of originality of a particular piece of writing. This is as it should be. But the emphasis on originality is a relatively recent phenomenon. It really came to the fore in the Romantic movement of the late 18th century, with its emphasis on the divine spark of individual genius. Before that, the art of imitation was as highly prized as originality, maybe even more so. A work was judged upon the ingenuity of the imitator.

SHAKESPEARE ANDhis contemporaries would not have understood this anxiety about adaptation. Of the 37 or more plays ascribed to him, only a handful contain material that might be described as "original". Even there, there may be sources as yet undiscovered by the scholars. Like his contemporaries in the Elizabethan and Jacobean theatre, perhaps the richest in the history of the language, Shakespeare borrowed endlessly, stealing plots without hesitation from other writers' books, pamphlets and poems, as well as borrowing from other plays.

When I was adapting Chekhov’s The Seagull in the 1980s for the Royal Court Theatre my agent at the time, Peggy Ramsay, said it would be like having “a privileged conversation” with the dead author. I have now had this mysterious and humbling experience again with the German playwright Frank Wedekind. In the end, if it’s any good at all, an adaptation should send you right back to the original with renewed respect for its achievement.

Wedekind's play, Spring Awakening, is about the repression of young people in 19th-century Germany. Obviously, my own play Christ Deliver Us!is deeply indebted to it, particularly in plot. But I have also tried to write a play drawing upon my own growing up in the 1950s. In this way I have tried to make the play more accessible to an Irish audience.

For instance, Wedekind’s play ends with a mysterious masked man, unidentified, unheralded. There is no other reference to him in the rest of the play. I think he represents the spirit and magic of theatre itself in the cabaret style of the time that Wedekind loved. It’s one of the most famous scenes in modern theatre, made more famous by the fact that Wedekind loved to play the part himself. There is a wonderful description by Brecht of his electric presence on stage, in a different part: “ugly, dangerous, brutal, with close-cropped red hair”. Because I was trying to tell Irish stories, this very German scene was one of the ones I had to change radically.

I LOVE PLAYSsuch as Spring Awakeningthat tell several stories at the same time, that have a variety of scenes, lots of spectacle and a loose episodic structure. They are expensive to produce and you don't see many of them around anymore. For this reason alone, we're very lucky to have our national theatre, the only theatre with the resources to put on a play like this in these bankrupt times, with a full cast of 25.

Any play that tries to address the exercise of power over young people by an alliance of church and State is bound to get connected to the recent headlines. Christ Deliver Us!was written before the publication of the Murphy Report. It doesn't contain sexual abuse because I never experienced such a thing as a youngster myself. It does have physical abuse, though, of young people by both teachers and parents. This was violent and systemic in my school days. Like all abuse this violence seeped through the whole culture. And it has a disturbing effect upon the young girl called Winnie, played by Aoife Duffin, in Christ Deliver Us! as it does, too, upon her model, the young girl called Wendla, in the Wedekind play.

Christ Deliver Us!by Thomas Kilroy is previewing at the Abbey Theatre in Dublin, opens on Tuesday and runs to Mar 13.