A "shared repository of centuries of British and Irish history" it may be, as the President, Mrs McAleese, told her guests last night. But even for a building as old as Aras an Uachtarain there is something new every day.
In what must have been one of the most novel entertainments laid on for visitors to the house, the British Prime Minister and his wife were treated to the Vienna Boys' Choir singing Danny Boy; wrapping their Teutonic tonsils around the words as though they'd been voice-trained in the Bogside.
It was not so much a clash of cultures as an embrace, to use one of Mrs McAleese's favourite words. And on a night when 200 guests from Omagh, Buncrana, Ballymoney and Spain - all in one way or another touched by the past summer's violence in the North - were also present, the "presidency of embrace" has rarely been so meaningful.
While Tony and Cherie Blair were only treated to one song from the choir, the rest of the audience had already had a full concert; but the music was interrupted after Danny Boy to allow the Prime Minister and his wife, and the President and her husband, to mingle with the other guests.
The air of agreement between Ireland and Britain in recent times last night extended even to the dress code. The outfits of both the President and Mrs Blair, and Tony Blair's tie for good measure, were all different shades of purple. And on a bitterly cold night, the ranks of Irish and British camera crews waiting outside to capture the Blairs' departure were gradually turning the same colour.
After a short private meeting with the McAleeses and the signing of the Aras visitors' book, the Blairs duly left, taking with them the crystal vase and designer scarf presented to them by the President.
Back inside, much interest had focused on the Quinn family from Ballymoney. Chrissie, who lost three of her sons when her home was fire-bombed at the height of the Drumcree crisis last July, was on the guest list, with her partner and surviving son.
They were nowhere to be seen during the period for which the media were allowed in, but the Aras confirmed they did arrive before the end of the night, having apparently had trouble finding the way.
Welcoming guests to "our house" for the evening, Mrs McAleese stressed the building's earlier history as home to the viceroys, for whom Dublin was "the second jewel in the British empire".
She added: "No one who comes here, whether from the Shankill or south Armagh, should feel uncomfortable."
Then, wishing her guests well as they approached what she knew would be a difficult Christmas for them, she quoted a line from Aeschylus, which Bobby Kennedy had used on the day Martin Luther King was shot:
"In our deep sleep, pain which cannot forget falls drop by drop upon the heart until, in our own despair, against our will, comes wisdom through the awful grace of God."
