It was an understandable mistake but no less embarrassing for being understandable. Several times, during the first day of Bertie Ahern's official visit to Mexico, the welcoming president, Vicente Fox, referred to An Taoiseach's companion as "Mrs Ahern".
By day two, Fox had been put straight, but by then the damage was done, the embarrassment caused and the question of Celia Larkin as First Lady without the seal of marriage had been stirred up back home.
Of course, Fox had no reason to assume Celia was anything other than Bertie's wife. She was everything else after all, official companion, prominent and public, his long-term partner, right-hand woman, as good as Mrs Ahern in everything but name and on paper.
And yet, Celia was not. She was not Bertie's wife, she was not -- according to an interview with him in this paper three years earlier -- ever likely to be his wife. And there's no such thing as being a little bit married.
A matter of months after the visit to Mexico, Celia Larkin's decades-long relationship with Bertie Ahern was officially over. Since the previous summer, speculation of its demise had ebbed and flowed but, finally, it came to an end. Apparently amicably, he remained in the limbo of his position as our separated-but-never-to-dare-divorce leader and she went to Limerick.
To date, neither has enjoyed a relationship to match the one they shared and last week, as she referred to An Taoiseach as her "life partner," Celia Larkin suggested she never would and was not looking. She may not have married him, but at the Mahon Tribunal last week, Celia Larkin claimed her rightful position as the greatest political wife this country never had.
Not that anyone allowed Celia away with assuming this position, however. No, if the Mahon Tribunal proved anything conclusively this week, it was that even now An Taoiseach's ex is neither liked, nor accepted, nor given the kind of civil treatment you can be sure Miriam Ahern would have been allowed in similar circumstances.
Celia was treated as a girlfriend, but she answered as a wife, testily defending the righteousness of her relationship and resisting all attempts to put her in her box, which began at Dublin Castle on Wednesday and continued in the catty read of her performance in the following day's papers.
Through it all ran a thread of "who does she think she is?" and the answer is that Celia Larkin is a woman who knows all about what Sean Lemass called "loylaty" (sic). So the right thing was never done by her, but last week, that didn't stop her doing the right thing.
Finglas-born, a Fianna Failer since her teens, Celia Larkin's public profile has always been tied up in her relationship with Bertie Ahern. She ran unsuccessfully for public office in the mid-Eighties, she worked for Bertie when he was Lord Mayor of Dublin in the late Eighties and yet, she did not really make an impact publicly until her relationship with the separated politician emerged in the early Nineties.
And the first real muttering of it was of the unkind, slightly grubby nature with which we have since become familiar. In 1992, when Charlie Haughey's departure might have seen Bertie run against Albert Reynold's for the FF leadership, the whispers around Leinster House were encapsulated into the nasty sneer that the people of Ireland "would want to know where their leader slept at night".
It was a low remark, summing up Bertie's post-separation relationship as about illicit sex rather than anything more respectable and it, apparently, postponed his plans to run for party leader.
As things turned out, it was another two years before the Fianna Fail/Labour coalition fell apart and Bertie succeeded Reynolds as leader of the party and, in 1997, became Taoiseach; Celia's status had changed. Notably, in her official position as advisor in the office of An Taoiseach, Celia got Dick Spring, the former Tanaiste's office and that was the first sign she wasn't going to be shoved in the shadows. At a Fianna Fail dinner to introduce him as the new party leader, Bertie had entered the room hand in hand with Celia and whether the applause was meant for them both or him alone, it was possible to assume the former.
Later, people who wished it so -- Bertie and Celia quite possibly among them -- took acceptance of a separated Taoiseach with a new partner as yet another symbol of an enlightened, open Ireland and tipped it as the start of something. And it was, for a while, though in the end it fell apart for all the old reasons. Can't commit, or won't commit, the end result remains the same.
Those who have met and spent time with Celia Larkin tell of a vivacious woman, self-confident, intelligent, driven, a match for Bertie Ahern in every way. They say she lent him a polish that does not come naturally to him, that she wasn't just an attractive presence in his life but an equal: equally politically astute, equally interested in the running of the country. She might have bought his shirts and most likely would not have advised him to wear that canary yellow suit, but Celia didn't iron them for him. If Bertie Ahern were looking for a partner, he found it in Celia Larkin, and then, perhaps, he let it slip away.
Hillary Clinton's visit to Ireland in October 1997 marked the first time Celia Larkin's name appeared alongside Bertie Ahern's on an official invitation to state event.
It was hugely significant, marking her as his life partner -- as she so properly put it last week -- and conferring respectability in a country where we still afford that only when wedding rings are involved. And so it went on. Celia stood side by side with Cherie Blair when Bertie met with Tony. She went to Buckingham Palace and dined with the Queen. In 1998, Celia and Bertie walked together, holding hands, along the Great Wall of China. Okay, she didn't live with him -- Celia always had her own Castleknock home -- and she wasn't invited to join his annual Kerry holiday with then-teenage daughters, Georgina and Cecilia, but the significant signs were there that this was for keeps.
In late December 1999, as the year, the century and the millennium came to an end, Bertie Ahern did an interview with this paper. It was an appropriate time to be both reflective and forward looking and yet, when asked if now was a good time for a fresh start to his private life, the right time to get a divorce from Miriam and marry Celia, An Taoiseach was adamantly not for advancing.
"It's not a possibility," said Bertie. "It stays as it is." He may have meant divorce was impossible, but the knock-on effect of that was that marriage to Celia was not on the cards. Ever. And, as most people understand, if a relationship is not moving forward, it's not going anywhere. Standing still is not an option.
The previous year, the Church of Ireland Gazette had criticised the relationship between Celia and Bertie. It found it "astonishing" that Celia accompanied Bertie on state visits and that he felt "no need to make apology for this situation".
The use of the word "apology" was significant, in its implication of shame and seediness, much as the casual use of the word "mistress" hurt Bertie, as he openly admitted. Later, in 2001 -- the same year as Celia was photographed wearing an impressive ring on her wedding finger -- Cardinal Desmond Connell was reported to have been dismayed by her inclusion on an invitation to a State function in his honour.
Not only that, but he was noted to have snubbed her at the event. If Celia hadn't got the message from Bertie's New Year, Sunday Independent, interview, surely it was coming through loud and clear from other quarters. About this time, rumours began of stresses on the relationship and in the summer of 2002, a senior FF advisor told this paper it was all off. An Taoiseach denied it, but did so in an interesting and telling manner.
"Look," he said, "I'm not single. I'm still with Celia -- at least that's who I was in bed with last night." It was a comment possibly born out of frustration but telling in how it referenced the mutterings from 1992, bringing the relationship back to bed and sex and, let's face it, not the kind of thing the nation's leader would say about a woman who was his wife.
By this time, Celia had quit her job as a civil servant, had a raised, independent profile as a beauty consultant and had given her own interviews, during one of which she had said, with certainty, that she saw marriage in her future.
Celia's statement of intent, as unequivocal as Bertie's, had, according to sources close to him, put pressure on the couple, and the following spring they split and he attended daughter Georgina's summer wedding alone, as had always been planned, but without the shadow of Celia.
When Celia Larkin moved to Killaloe last year, Bertie opened her salon in Limerick's Castletroy Park Hotel. The pair were very friendly, apparently pleased to see each other, comfortable in each other's company and, naturally, there was speculation as to why they had ever split. But being good together is not always enough, perhaps.
That it is over, however -- and probably painfully over -- does not denigrate the relationship for Celia Larkin, it would seem. If she is bitter or disappointed that her relationship with "life partner" Bertie never became one of man and wife, it wasn't apparent in Dublin Castle last week.
Celia Larkin did not come to the Mahon Tribunal as a woman disappointed, but as one defensive of the man she once wanted to marry, of his conduct, of her part in how he conducted himself. If she was blithe about the money she deposited for him all those years ago, maybe it was because she took involvement in his financial affairs for granted, as a sign that they were a team, handling their finances together.
She applied humanity to the proceedings, her recollections triggered by the little, ordinary things like biscuits and purchases of household linens and of how she made nice with the wife of her partner's business associate.
Celia Larkin's answers -- nastily read as tetchy and snippy, where a man would be considered assertive if he answered similarly -- were based on real-life detail rather than diary dates and she brought the domestic into the tribunal, made a man of An Taoiseach.
For once, we had a glimpse of just how like a marriage was the relationship between Celia Larkin and Bertie Ahern. In all but the crucial way.
He never made a "respectable" woman of her, but loyal to the end, keeping faith in the man who was her life partner whether he wed her or not, Celia Larkin was wifely when she came to the Castle. No one thanked her for it, picking apart instead her pink suit, her hair-do and her smooth skin, but, quietly, one hopes Bertie saw Celia for what she was, a deserving second wife. Albeit a little too late.