It was almost a shock when she walked into the room. It was that shock of recognition which comes with encountering someone who you've never met, but feel you know for years and years.
It's just that she's so familiar -- the slightly square face framed by white curls and topped with a large hat, the sharp eyes taking in everything around her, the handbag, the gloves and occasionally the wide smile.
We've seen the face of Queen Elizabeth so many times on the telly and in newspapers and magazines; animated at Ascot, stony-faced during the perilous days after the death of Princess Diana, disconsolate amid the ashes of Windsor Castle, content during the wedding of her grandson William. But we've never seen her in the flesh before.
When she set foot on the soil of the Irish Republic yesterday, she had been on the British throne for 59 years and 100 days, she had undertaken 380 state visits to all sorts of far-flung outposts around the globe. But she had never made the short trip to her nearest neighbour.
Of course she hadn't. For years there was too much bad blood, too much violence, too many long memories of oppression and atrocities, too much suspicion and mistrust between two countries which, on a clear day, can wave to each other across the Irish Sea.
But then peace came dropping slow. The ballot box outlived the Armalite, as Ireland inched forward and tried to shake off the grip of the hungry ghosts of history.
There were symbolic handshakes and historic elections and the spine-tingling singing of the British national anthem in Croke Park, the heartland of Irish nationalism and scene of a bloody massacre.
However, there was one last flourish required; a definitive scribing of the words The End at the close of the final chapter of the long, convoluted, complex tale of two countries.
And here she was, the British queen, the living link in a royal chain stretching back through the hundreds of years of shared history. Here she was, pen at the ready, to signal the end of one story and the start of something new.
The royal entourage was a little late arriving from Baldonnel down the sweeping driveway into Aras an Uachtarain (though given the traffic restrictions, for once congestion at the Red Cow couldn't be blamed).
She stepped out of the Range Rover and was greeted by President McAleese. It was a warm meeting in a formal setting -- the two heads of state have met on six previous occasions, going back to 1998.
But most significantly, it was the meeting of equals. The queen was wearing the distinctive green outfit which had signalled from the moment she had stepped from the plane that she was here to underline the shared history of the two countries rather than to emphasise the differences.
And then she and the Duke of Edinburgh were escorted into the Aras to meet the Taoiseach and then down the broad Francini corridor lined with bronze busts of our presidents, and into the State Reception Room to sign the Visitors' Book.
She entered the room, head down, apart from a quick glance at the row of media, and got down to business at the little square wooden desk. Then it was Prince Philip's turn. "Sign there," the queen pointed out to him helpfully.
Then the four left for a brief ceremony on the steps of the former residence of a succession of British viceroys and lieutenant generals, until it became the residence of the president of the fledgling Irish Republic in 1937. As the first notes of 'God Save the Queen' began, the muffled boom of a 21-gun salute ended with the last notes of 'Amhran na bhFiann', as an honour guard may have been the first to inform the queen that her title as Gaeilge is Banrion Eilis a Do.
Meanwhile, a gathering of guests had convened around the corner of the Aras for a tree-planting ceremony, in which the queen would shovel some earth on an Irish oak.
It had the atmosphere of a genteel afternoon tea-party as the gathering waited for the royal couple. Tanaiste Eamon Gilmore had a long chinwag with British Foreign Secretary William Hague. Also in the group were John Hume and David Trimble, important pieces in the painstaking jigsaw of the peace process.
And then slowly down the gravel path strolled the queen and the president, engrossed in a deep conversation, while behind them Prince Philip and Martin McAleese nattered like long-time buddies.
It was a moment to give all who saw it pause. The two women, the queen clad in vivid green and Mary McAleese in cerise pink, stood out against the verdant backdrop of trees and an impeccable lawn.
There was an odd sense of normality about the scene, an informality that belied the fraught run-up to the visit, the meticulous planning and the understanding of the significance of it all.
Without ceremony, the queen passed over her black handbag to her Lady in Waiting, Lady Diana Farnham, and wielded the spade like the expert she is. One can only imagine how many trees she has planted on her travels around the world.
Afterwards the Peace Bell beside the tree was rung once by schoolchildren Danny Rea from the North and Leah Ennis from Cabra, and the president promptly called them over for a quick chat with the queen.
And then it was off to lunch, which was attended by a wide smorgasbord of guests including writer Edna O'Brien, chef Rachel Allen, Sister Stanislaus Kennedy, Micheal O Muircheartaigh and the posse of politicians.
What would they have all talked about? The hand of history on all their shoulders?
Maybe. But perhaps the conversation was about the weather and the family. The sort of normal stuff you talk about when you have the neighbours in.