Ibsen became spiritual godfather to the Irish literary movement by showing how a great writer could invent a modern nationality, writes Fintan O'Toole

In 1904, as he and his colleagues were preparing to launch the Abbey Theatre, WB Yeats felt sure of at least one thing: "So far as we can be certain of anything, we may be certain that Ireland, with her long National struggle, her old literature, her unbounded folk imagination, will, in so far as her literature is national at all, be more like Norway than England or France." Looking back nearly 20 years later as he accepted the Nobel Prize, he returned to the same thought: "Nor do I think that our Irish theatre could have ever come into existence but for the theatre of Ibsen and Bjornson."

Both quotations hint at one of the reasons Henrik Ibsen mattered so much to Irish writers in the decades either side of his death in 1906: being Norwegian was a good way of not being English. It was also, because of Ibsen's modernism, a good way of belonging to a small nation without being mired in an obscurantist past.

Yeats's acknowledgement of Ibsen's role as spiritual godfather to the Irish literary movement is all the more impressive because it was made in spite of deep ambivalence. In some respects, Yeats disliked Ibsen's work, especially the realistic plays that made the Norwegian such a famous and controversial figure in the English-speaking world.

After seeing the first English production of A Doll's House in 1889, Yeats "resented being invited to admire dialogue so close to modern educated speech that music and style were impossible". Ibsen "became in my eyes the chosen author of very clever young journalists, who, condemned to their treadmill of abstraction, hated music and style".

Later, Yeats the delivered the most brutally witty put-down of Ibsen, when he sniffed in Rosmersholm "the stale odour of split poetry".

Yet Yeats also proclaimed Ibsen in 1901 "the one great master the modern stage has produced". And even in recalling his negative reactions to A Doll's House, he felt compelled to add "and yet, neither I nor my generation could escape him because, though we had not the same friends, we had the same enemies".

Ibsen was inescapable for Irish writers in the early 20th century because he reinvented the theatre as an arena for social and artistic seriousness, because he showed how a great writer could practically invent a modern nationality, and because he made a visceral connection between the urban intellectuals and the folklore of the countryside. He also had the inestimable attraction of having a body of work so varied that most writers could find their very own Ibsen.

The impossibility of escaping Ibsen's influence is nowhere more evident than in the work of the greatest and most distinctive Irish playwright of the era, John Synge. Synge set himself up in public as the anti-Ibsen, condemning, in his preface to The Playboy of the Western World, the latter's "joyless and pallid" language - a judgment based, of course, on his reading of translations into German (which he read as early as the late 1880s) and English.

Yet the mark of Ibsen on Synge is unmistakable. Synge's unfinished prentice play When the Moon Has Set is, as WJ McCormack has pointed out, an attempt to re-write Ghosts. The Shadow of the Glen is a concentrated and comic version of A Doll's House, with the same escape from a joyless marriage and even the same name (Nora) for its heroine. Even The Playboy itself has echoes of An Enemy of the People.

What is especially striking about the Irish relationship with Ibsen is that it largely transcended politics and the culture wars of the 1890s and 1900s. Ibsen was initially a source of enraged controversy in the Anglophone world. The row over Ibsen in England was initially dramatised by a very public dispute between two Irish brothers.

Augustus Moore made his journal The Hawk into a platform for attacks on the writer he labelled "Ibscene". His brother, the novelist George Moore, took up the Ibsenist cause, and attended the first reading of Ghosts at the home of Karl Marx's daughter, Eleanor.

This leftist Ibsenism was most famously articulated by another Irishman, Bernard Shaw, in his short book (originally a lecture to the Fabian Society) The Quintessence of Ibsenism, published in 1891. Shaw declared Ibsen's plays "much more important to us than Shakespeare's" because "the things that happen to his stage figures are the things that happen to us".

Shaw's quintessence of Ibsenism was, of course, the quintessence of Shavianism: social and moral reform through the exposure of bourgeois hypocrisy. The book itself seems to have been inspired in part by the fall of Charles Stewart Parnell and the torrent of moral self-righteousness it released.

Yet Shaw's Ibsen - a radical battering-ram pounding on the doors of reactionary hypocrisy - was assimilated with surprising ease into Catholic nationalist culture in Ireland. There were certainly those who were on their guard against the threat of Norwegian pollution. DP Moran's The Leader described The Shadow of the Glen as "an evil compound of Ibsen and Boucicault".

The former MP Frank Hugh O'Donnell attacked Yeats and the incipient Abbey in 1904 as a "witch's cauldron of aboriginal superstition and Ibsenite neo-paganism".

Nevertheless, Ibsen was championed even by some of the Catholic and nationalist figures who led the charge against Synge over The Playboy. The first performances of the Irish Literary Theatre included Edward Martyn's sub-Ibsen play The Heather Field and Fred Ryan's equally Ibsenist The Laying of the Foundations. Martyn is especially interesting, for he combined an intense Catholicism with a devotion to Ibsen.

According to Yeats, Martyn "read Ibsen and the Fathers of the Church and nothing else". When A Doll's House was produced in Dublin in 1903, Arthur Griffith considered it a "great play".

In a rather bad poem decrying the bad taste of Dublin audiences, Griffith linked the Norwegian master with the great figures of theatre history: "Should Shakespeare, Ibsen, Moliere come/The Dublin boxes stay at home."

Likewise, the playwrights such as Padraic Colum and William Boyle who appealed to Catholic middle-class audiences, whether at the Abbey or Martyn's rival Irish Theatre, were often those who modelled themselves most closely on Ibsen. During rehearsals for George Russell's Deirdre in 1901, James Cousins noted that "Padraic Colum lay out on the grand piano on the stage of the Coffee Palace Hall learning to be an Irish Ibsen."

William Boyle, who provided the Abbey with some of its earliest hits, was also a follower of the great Norwegian, modelling, for example The Great Dempsy (sic) (1906) on An Enemy of the People.

The most important legacy of Ibsen's influence on early 20th-century Ireland was not, however, in the theatre. In 1900, Ibsen sent a short note in Norwegian to his English champion William Archer, referring to an essay on When We Dead Awaken in Archer's journal The Fortnightly Review: "I have read or rather spelt out, a review by Mr James Joyce in the Fortnightly Review which is very benevolent and for which I should greatly like to thank the author if only I had sufficient knowledge of the language."

Joyce, who had learned some Norwegian in order to be able to read Ibsen, translated the note and, deeply moved, wrote back to his idol: "I am a young Irishman, 18 years old, and the words of Ibsen I shall keep in my heart all my life."

In 1901, Joyce again wrote to Ibsen, to wish him a happy 73rd birthday. In this rather gauche fan letter, Joyce declared himself a passionate missionary: "I have sounded your name defiantly through a college where it was either unknown or known faintly and darkly. I have claimed for you your rightful place in the history of the drama. I have shown what, as it seemed to me, was your highest excellence - your lofty impersonal power . . . But we always keep the dearest things to ourselves. I did not tell them what bound me closest to you. I did not say how what I could discern dimly of your life was my pride to see, how your battles inspired me - not the obvious material battles but those that were fought and won behind your forehead - how your wilful resolution to wrest the secret from life gave me heart, and how in your absolute indifference to public canons of art, friends and shibboleths, you walked in the light of inward heroism."

Joyce, whose great novel is about a man in search of an alternative father, found his own artistic father-figure in Ibsen. He would learn to be less self-dramatising and less romantic (his alter-ego Stephen chooses as a father not a lofty impersonal power like Ibsen but the down-to-earth Bloom). It was Ibsen, however, who gave him the courage to think of himself as a free artist. After paying the homage of his own Ibsenist play Exiles, he freed himself of Ibsen, too. But like so many of his contemporaries, his journey from Ireland to the centre of Europe went via Norway.

Henrik Ibsen: inescapable for Irish writers in the early 20th century

GB Shaw: 'Much more important to us than Shakespeare . . . the things that happen to his stage figures are the things that happen to us'

James Joyce: 'In your absolute indifference to public canons of art, friends and shibboleths, you walked in the light of inward heroism'

WB Yeats: ' . . . Nor do I think that our Irish theatre could have ever come into existence but for the theatre of Ibsen and Bjornson'