Watching the faces of the guests at the top table in Dublin Castle on Wednesday night, I noticed the Nobel Laureate Seamus Heaney. He was listening with rapt attention to the Queen as she spoke of reconciliation and a shared future. In a memorable affirmation of his identity Heaney once wrote:
Be advised, my passport's green
No glass of ours was ever raised to toast the Queen.
[Open Letter, 1983].
Heaney has never been an atavistic writer. His vision is consistently tolerant and generous. But when he wrote that poem in 1983, the notion of any Irishman from a nationalist background toasting an English monarch, let alone in Dublin, was unthinkable.
The Dublin and London governments were only then beginning to struggle towards détente after bitter years of mistrust.
The Northern Ireland political parties were indulging in their relentless cycle of mutual blame. And 87 people, British and Irish, Catholic and Protestant, were killed in the continuing violence.
Among them was 20-year old Private Mark Curtis from Grimsby, murdered by the IRA, and Thomas "Kidso" Reilly, an unarmed Catholic shot by a soldier in Ballymurphy. His last reported words were, "You won't call me an Irish bastard."
Curtis and Reilly are not only names from the list of three-and-a-half-thousand people who died in three decades of the Troubles.
They belong to a greater community of the lost, the hundreds of thousands of the dead, from Monaghan to Warrington, from stony famine graves in Kerry to the cemeteries of Belfast and Birmingham.
Yet the sacrifice of those centuries did not, as WB Yeats once wrote, "make a stone of the heart."
When Queen and President bowed their heads at the Garden of Remembrance, and stood in silence at the war memorial in Islandbridge, they showed humility and generosity that history might have suggested was impossible.
Their gesture emphasised the greatest principle of peacemaking: to reconcile you must acknowledge the pain of all.
What is being swept away in these memorable days is the notion that any side in the story of Ireland and Britain can claim a monopoly on suffering or use the past as an alibi.
The British establishment too often adopted an attitude of bewilderment with the Irish question, most memorably expressed by Churchill and his weary evocation of the "dreary steeples of Fermanagh and Tyrone" where the quarrel of the two tribes defied rational explanation.
It was as if the bloody business on the other side of the Irish Sea was down to some genetic predisposition to hatred on the part of the natives, Catholic and Protestant.
As Britain changed and modernised so too did the attitude to Ireland. It is in the figure of Margaret Thatcher that we can trace a real evolution in British thought and action. A target of IRA assassination she nonetheless grasped the necessity of creating a framework that could begin to meet nationalist aspirations, a recognition of an all-Ireland dimension to the Ulster problem. Together with Garret Fitzgerald, whose death occurred yesterday, Thatcher signed the Anglo-Irish Agreement in 1985.
For the first time the British state acknowledged and gave institutional expression to the right of Dublin to have a say in the affairs of Northern Ireland. The deal infuriated Unionists and was denounced as meaningless by militant nationalists.
But unlike Harold Wilson in 1974, Thatcher held her nerve in the face of Unionist strikes and demonstrations. It was a pivotal moment of political courage and propelled Unionists into intense self-questioning. Thatcher and Fitzgerald paved the way to Good Friday in 1998 and Dublin Castle this week.
For their part the overwhelming majority of Irish people have long ceased to see themselves as victims of the English. We have moved on. The old and understandable tendency of the colonised to define their identity in opposition to the conqueror has vanished. It is possible now to recognise, as the Irish President Mary McAleese made clear in her speech, the unique cultural gifts that have flowed from the mingling of British and Irish identities. In a time when the language of shared heritage and reconciliation is now commonplace, it is also worth recalling, those who spoke of such things when it was far from easy. I think of a historian like Professor Roy Foster of Oxford University who, more than any other academic, gave us a story of Ireland that overturned the dangerously simple morality tale that endured for decades in Ireland. His practical patriotism helped to open the minds of a new generation. I think too of a man like Bishop Edward Daly of Derry who witnessed the horror of Bloody Sunday but remained one of the most profoundly humane of men, one who denounced equally the injustices of the state and the bombings of the IRA.
Throughout the darkest of years there were people who kept alive the idea of a shared future. My friend, the poet Michael Longley, gave us verses to calm many an angry hour. Though living in the heart of Belfast and witnessing the violence at first hand he remained a civilised man, perhaps the greatest achievement of any who must live amid sectarian hatred. In Ceasefire, written to mark the IRA's 1994 statement, he reached into the Classical past and the myth of Troy to offer an example for Ireland:
I get down on my knees and do what must be done
And kiss Achilles' hand, the killer of my son.
The first royal visit to the Republic reminds us to salute the peacemakers, including those like Gerry Adams, Martin McGuinness and the late David Irvine, who made the journey from being men of war to men of peace. There are those who will continue to kill in the name of Ireland. But by standing together, and by speaking with such humility, Queen and President expressed the hope of an overwhelming majority. No gun or bomb can change that now. But by standing together, and by speaking with such humility, Queen and president expressed the hope for peace of the overwhelming majority of the people of these islands.
The writer is a BBC special correspondent. His series 'Story of Ireland' airs on BBC 2 next Tuesday at 7pm