When S∅le de Valera appointed Marie Donnelly to be chairman of the board of the Irish Museum of Modern Art in February 2000, she had no reason to imagine that a talent for controversy might be one of the abilities she would bring to the job.

Until the dispute between the IMMA director, Declan McGonagle, and the board hit the headlines a little over a year ago, Donnelly's public profile was based on her highly successful tenure as chairwoman of the Irish Hospice Foundation, during which she oversaw the production and promotion of The Whoseday Book in 1998.

However, she and her husband, Cork-born bookmaker and businessman Joe Donnelly, were known in cultural circles as serious art collectors. As such, they operated on a level unprecedented in Ireland and were as exceptional here as Charles and Doris Saatchi were in Britain.

While other well-known Irish collectors, including, for example, Pat and Antoinette Murphy and Vincent and Noeleen Ferguson, assembled substantial art collections, they tended to concentrate on work by Irish artists.

The Donnellys broke the mould by acquiring substantial pieces by the kind of big-name international artists who turn up in the world's major museums, such as the celebrated German Georg Baselitz, the controversial American Julian Schnabel, the modern master Willem de Kooning, and younger Brit artists Sarah Lucas and Gary Hume.

Their focus on international names does not mean they were indifferent to the Irish scene.

Their purchase of a Robert Mapplethorpe photograph from the Gallery of Photography, for example, was a significant boost to the exhibition of his work here.

And though it has been said it is not strictly true that they never buy work by Irish artists. Belfast-born Mark Francis, for example, features in their collection. But the relative rarity of works by Irish artists in their possession did add to the negative publicity during the IMMA controversy.

They move comfortably in international art circles, both serving on the International Council of the Tate Gallery and on the international board of New York's Museum of Modern Art.

Far from being a kind of social accessory, their interest in art and design runs deep. Anselm Kiefer, regarded by many as the most significant German artist of his time, and his wife, Renata, are numbered among their good friends, and Marie Donnelly is said to get on genuinely well with the slightly forbidding Sir Nicholas Serota, Tate Gallery supremo and the man generally viewed as the most powerful figure in the contemporary British art world.

Marie Donnelly, nΘe O'Neill, was born in Youghal in 1950 and attended the Presentation Convent there. She and Joe Donnelly, her senior by a few years, married young. They have four children, three sons and one daughter. Joe Donnelly worked in the family on-course bookmaking business, one of the country's leading bookmakers. Now he also has extensive property investments.

An observant, quiet-spoken man, completely free of affectation, he has a passion for and is extremely knowledgeable about 20th-century design, designer furniture and contemporary art.

The Donnellys' house, built into the Killiney coastline, is a big, spectacular, uncompromising piece of minimalist architecture which serves as a gallery for their art collection. They entertain lavishly, and among regular guests is the Minister for Finance, Charlie McCreevy, who shares with Joe Donnelly an interest in horse racing.

Marie Donnelly follows haute couture and has often appeared in public in striking designer outfits.

Her interest in fashion led to her involvement in an innovative showcase for Irish clothes designers in the St Stephen's Green shopping complex, The Galleria (where Habitat is now located) in the 1980s.

She was a founder member of the Irish Hospice Foundation in 1986 and became active in fund-raising campaigns, joining the board in 1989 and becoming chairwoman in 1997. She also served on the board of the Douglas Hyde Gallery in Trinity College in the 1990s, but there is no indication that she contributed greatly to the development of the gallery and she never occupied the chair.

Her impressive management of The Whoseday Book project (the idea for which was originally mooted by columnist John Waters) undoubtedly boosted her confidence.

The creation of the book involved enlisting the support of many of the best-known artists and writers in the country, including Seamus Heaney and Louis le Brocquy. It was an imaginative venture, brilliantly executed, that brought in some £2 million.

She took on the position at IMMA with the conviction that a change of direction was needed at the museum. Between her appointment in February and the following autumn, she clearly came to the conclusion that a change of direction meant a change of director. She was, reportedly, particularly annoyed at the debacle of the poorly produced and error-ridden catalogue for the museum's disappointing turn-of-the-century exhibition of Irish art, "Shifting Ground".

Any impression that Declan McGonagle would respond positively to the notion of moving on was dramatically dispelled when he sought an injunction to prevent the board advertising his job last November.

He got his retaliation in first, and Donnelly found herself fighting an image battle for which she was ill prepared. Typecast in the media as a socialite, she found herself pitched against a formidable opponent in an increasingly personalised confrontation.

The fact that there was not a shred of evidence to suggest that she harboured any ill will towards the museum's universally lauded community arts programme counted for naught. The public perception was that she was somehow against community arts and in favour of international blockbuster exhibitions, that she was a wealthy socialite out to bring down a man of the people.

A major problem for her was that the stark outline of the publicised account of the board's treatment of McGonagle - that he had been summarily informed that his job was being advertised and his contract would not be renewed - made it difficult for anyone to support her position, at least openly.

Even those critical of aspects of McGonagle's curatorial style, and there were many, felt that he was being badly treated.

She found herself isolated, locked into a bitter dispute without the clear support of her board, which quickly divided on the issue. Even those sympathetic towards her say that she is in many respects politically naive, and that she crucially lacked the people skills she might have built up throughout a conventional career, skills that might have enabled her to manage her board with greater tact and effectiveness.

She is not part of any coterie or faction within the Irish art world and hence did not have a relevant network of friends to whom she could automatically refer.

Although numerous conspiracy theories have been circulated, it seems clear that as chairwoman of IMMA she always acted alone, out of personal conviction. Even when, in the early days of the dispute, she faced an unprecedented battery of opposition from various cultural and business quarters, she kept her nerve and stood her ground with steely resolution.

When Declan McGonagle, after mediation by Paddy Teehan, won the offer of a further five-year term and opted to quit last April, with a substantial financial settlement, it seemed that Marie Donnelly had got at least part of what she wanted.

But it was at considerable cost, to the public purse, to herself in terms of the bruisingly bad publicity she had endured, and to IMMA itself. Further problems loomed when it became clear that there were few plausible applicants for the post of director. Yet with Brian Kennedy among them it seemed that things might work out in the end, for Marie Donnelly and for IMMA.

A dynamic and enormously capable individual, and no stranger to controversy himself, Kennedy was one of the few qualified contenders capable of handling the practical and other difficulties at Kilmainham.

There were, however, further pitfalls waiting, on at least two fronts. First there were the last-minute, highly publicised resignations of Niall Crowley and Terry Prone from the IMMA board in protest at what they viewed as irregularities in the selection procedure. Their action unavoidably put a question mark against the appointment.

Less obviously but perhaps more ominously, there was the antipathy of the Department of Arts, Heritage, Gaeltacht and the Islands towards Brian Kennedy.

A source close to S∅le de Valera said that the Department was incensed at the prospect of Kennedy's appointment and would be prepared to fight it. The dislike is generally thought to extend back to the controversial decision to allow the Book of Kells to travel for exhibition in Australia two years ago, when Kennedy did not make friends in the Department, to say the least.

After Brian Kennedy's withdrawal, the last straw for Marie Donnelly was probably when she found herself again embattled, at odds not only with two of her own board members and with S∅le de Valera, the Minister who had appointed her, but also with members of the interview panel.

In the final analysis IMMA badly needs someone with Brian Kennedy's flair and practical skills. It has lost him in tangled circumstances that reflect badly on almost everyone, including the Department, the board of IMMA and Marie Donnelly herself.

She may draw cold comfort from the fact that, throughout her annus horribilis, she has at least pursued a consistent and coherent strategy, one that may, eventually, deliver a change of director and direction at IMMA, albeit in her absence.