By Martina Purdy
BBC NI political correspondent
The term "ice-age" has now entered the peace process terminology.
Relations have thawed in the past few months
It began on Monday at the British-Irish Council when Ian Paisley teased Bertie Ahern that he had "survived the ice-age".
The anecdote swiftly reached the ears of RTE's Northern Editor Tommie Gorman, who well understood that the remark was a reference to the snowballs his younger self had thrown at former Taoiseach Sean Lemass in 1965.
So as Ian Paisley arrived for a news conference in Armagh ahead of the North-South Ministerial Council, Mr Gorman shouted: "Is the ice-age over?"
The first minister, beside his old foe, Martin McGuinness, now a grinning deputy first minister, decided to play along.
"Well," he said, "there was a time when the ice-age was, when I threw snowballs at certain people from the south but I was congratulating the taoiseach that the ice-age was over and he escaped the snowballs."
Mr McGuinness, who did not seem at all surprised by his partner's remarks, waited for his turn to speak, describing the significance of the day.
Two months into the administration and there was no sign that this mutually friendly double act was descending into any kind of acrimony.
Quite the reverse, as relations seem to be getting better.
Indeed, the first and deputy first minister arrived with remarkable synchronicity.
Ian Paisley's black automobile pulled up, with Martin McGuinness' just behind.
Then Ian Paisley's door opened and out he came, breaking into a smile when his political partner, in a kind of political Riverdance, jumped out from the car behind.
Contrast this with the first NSMC meeting in Armagh in December 1999 when David Trimble and Seamus Mallon, in what seemed like a metaphor for the disjointed relations in the First and Deputy First Minister's office, failed to arrive together.
This 1999 NSMC meeting was less free flowly
As the pair passed the cameras, a reporter shouted at Ian Paisley, asking if he was happy to be in Armagh.
In other words, was the DUP leader who once railed against north-south institutions, and shunned the last NSMC, miserable at the prospect of ending his boycott?
Was he heck! Mr Paisley promptly declared he was happy to be in Armagh, the city of his birth.
The mood was even lighter after the formal meeting which lasted half an hour longer than anybody expected.
Not because there was a row but because when they strayed from the agenda, the two dozen ministers from both sides of the border were spontaneously exchanging ideas.
At the post-meeting news conference, keen observers of Mr Paisley's language noted his use of the term "both parts of Ireland" and his praise for Dublin's helping hand on economic matters.
Indeed, the first minister was now throwing metaphorical snowballs in the direction of his own government.
He told the media the British government had to undo the damage done under direct rule, notably the lack of investment in the water service.
He said Gordon Brown could not leave us floating in the Atlantic.
As for Mr McGuinness, he remarked on the change in dynamic at the NSMC meeting, recalling the comparatively dull meetings that had gone before when it managed to meet just four times between 1999 and 2002.
The view was echoed by Taoiseach Bertie Ahern, who also rowed in behind Mr Paisley by suggesting it was St Andrew's that had made the change possible.
This was no doubt manna for Mr Paisley who has insisted it was a new accountability factor wrought by the St Andrew's deal that made the NSMC palatable.
But Sir Reg Empey, the Ulster Unionist leader who worked the last institutions, gave his own verdict.
It wasn't, he insisted, the institutions that had changed but Ian Paisley, whom he said had put his "final thumbprint on the Belfast Agreement".
But even Sir Reg knows there is no point in bitterly debating this point, as the public do not seem interested in the details of the change.
Most are too busy absorbing the transformation.