IN the sumptuous surroundings of St George's Hall in Windsor Castle, Queen Elizabeth made a solemn vow, a final, dramatic healing of our two countries' tangled, troubled history.
“My family and my government will stand alongside you, Mr President, and your ministers, throughout the anniversaries of the war and of the events that led to the creation of the Irish Free State.”
The comment is viewed as a clear signal the royal family will participate in commemorations of the 1916 Rising and the War of Independence.
There was utter silence, but it was an electric moment, another unforgettable declaration by the queen, almost three years after she stood in Dublin Castle and opened her address with perfectly spoken words of Irish.
Next to her, President Michael D Higgins looked visibly moved as the long shadows of gunmen which had stretched across Ireland and Britain from 1916 to recent years receded into the shadows.
A few feet away, and 15 places to her right, sat Sinn Fein's Martin McGuinness. How everything has changed.
And what a glittering stage upon which to make such an announcement.
Under beautiful chandeliers and gleaming silver suits of armour standing to attention in lofty niches in the walls, 160 guests sat at the longest table in the land – 160 feet long and weighed down by gilded candelabra, meticulously placed glasses – five in all at each place.
The queen's modulated, crystal-cut words hung in the perfumed air.
”We who inhabit these islands should live together as neighbours and friends. Respectful of each other's nationhood, sovereignty and traditions,” she said.
“We will remember our past, but we shall no longer allow our past to ensnare our present”.
It was the culmination of an extraordinary day, which had begun early in London when Prince Charles and Camilla greeted President and Sabina Higgins at the Irish Embassy, escorting them to Windsor for the formal greeting by the queen. And what a warm welcome it had been.
In the quadrangle of Windsor Castle – the residence the queen considers home, rather than Buckingham Palace, which is regarded more as the office by the royals – the full panoply of royal pomp was displayed.
This was followed by a private lunch at Windsor Castle and a relaxed tour of the castle's Irish collection of artefacts, before the President headed back to London to lay a wreath at the Tomb of the Unknown Warrior in Westminster Abbey, followed by a formal address to both Houses of Parliament in Westminster.
But the highlight of this extraordinary day was the state banquet, the only occasion where the voices of both the queen and the President will be heard.
Irishmen and women sat side by side with British royalty and citizens. The Taoiseach was sitting beside David Cameron and on the other side of the prime minster was Mary McAleese.
Tanaiste Eamon Gilmore was on the the left of the queen, with Princess Anne on his other side.
Martin McGuinness stood and joined in a toast to the queen, Prince Philip and the people of the UK as an orchestra played God Save The Queen.
But the attendance of the North’s Deputy First Minister Martin McGuinness cast a shadow over the event on the British side, due to his past as an IRA leader.
Mr McGuinness' presence dominated coverage of the event in the British media.
There were plenty of famous faces – actors Judi Dench and Daniel Day Lewis, rugby star Brian O'Driscoll, Prince Charles and Camilla, and Terry Wogan.
This was the full bells-and-whistles, with the queen and Duke of Edinburgh leading a formal procession into the hall.
President Higgins, resplendent in tuxedo and white bow tie, spoke fluently about the ties between the nations.
“Ireland and Britain live in both the shadow and in the shelter of one another, and so it has been since the dawn of history,” he said.
But just as with her speech in Dublin Castle during that unexpectedly joyous visit three years ago, the 87-year old monarch totally stole the show.
She even cracked a joke, remarking that “it took someone of Irish descent, Danny Boyle, to get me to jump from a helicopter”, she deadpanned to laughter, a reference to her surreal appearance in the opening ceremony of the London Olympics two years ago.
This was a delicately balanced speech of looking back and looking forward.
She referenced poet Seamus Heaney and echoing his famous lines, how his poetry “reflected the changing circumstances of Northern Ireland, as hope and history jarred and then slowly began to rhyme”.
The queen's small foot took another giant stride along the fragile path to peace.
Perhaps it was fitting that hope and history spoke in harmony in the restored grandeur of St George's Hall which was destroyed by a devastating fire in 1992.
But it rose from the ashes, and brick by brick was rebuilt.
And it was in this symbol of determination that the queen welcomed the President and closed the circle.
She or members of her family will attend another commemoration of a different kind of Rising. And yet more ghosts will be laid to rest.
This was no ordinary state visit – it was the first by an Irish head of State.
The hand of history brushed Michael D Higgins' shoulder at every turn.
I am writing this from a small cafe just opposite the Old Bailey. For many Irishmen of my vintage, the Old Bailey is synonymous with IRA terrorists as well as innocent Irish people stitched up for crimes they didn't commit. In my head, the Old Bailey reminds me of the 1970s and 1980s, a time when relations between Ireland and England were at their most strained.