It was a moment of such improbability that it sets a new benchmark against which the future will judge unlikely events that are still to come.
Ian Paisley and Martin McGuinness are an improbable team
The clerk of the Stormont parliament read the long and convoluted oath of office which all Northern Ireland ministers must affirm and then, in the space of a minute, first Ian Paisley and then Martin McGuinness rose to their feet and acknowledged they would be bound by their new duties.
The proceedings were bald, and businesslike and lacking in poetry, but to anyone with a head for history or a heart in Ireland, worlds of meaning hung on every syllable.
Sworn enemies were sworn in. Power was shared. Northern Ireland found itself poised between a past of violence and division and a future which promises if not instant harmony, then at least growing co-operation.
The roots of the conflict stretch back to the reign of Henry II who died in 1189. In the 41 years since the modern Troubles started in 1966, more than 3,500 people have died.
The negotiations to get the current generation of politicians to this point have lasted twice as long as the talks which ended the Napoleonic conflict and the First and Second World Wars put together.
Martin McGuinness and Ian Paisley have been leaders within their respective nationalist and unionist communities for decades - and yet until recently in an area with a population the size of a large English county or a small American city, they had never met.
For years, they were icons of intransigence, eye-balling each other across a wasteland of violence.
When the British and Irish governments brokered a power-sharing deal between Northern Ireland's more moderate, centrist parties in 1974 it was wrecked by violent republicanism on the one hand and street unionism on the other.
Martin McGuinness and Ian Paisley were in the thick of the opposition to the political deal in those days, although of course they were divided even in their opposition.
Slowly, the movements they represent have evolved away from the sterile hatreds of the past towards the hopeful uncertainty of democracy and power sharing.
Old enmities have been foregone, rather than forgiven or forgotten and the two men would still see Northern Ireland's past and future in very different terms. It is just that they have decided jointly to manage the present.
Will it work? Well the early signs are that it really might.
In the speeches which followed the formal business in the chamber we got a curious insight into how similar their political style can be even though they embody the rival aspirations of United Kingdom and United Ireland.
The Troubles in Northern Ireland lasted decades
Ian Paisley, in his speech which quoted from the Song of Solomon also read a poem written by the widow of an RUC officer.
Martin McGuiness included a story about how a 100-year-old woman from Ardara in County Donegal had phoned him after the recent elections here to say that she was looking forward to seeing him in government alongside Ian Paisley.
Folksy stuff, certainly, but both men do it well and both men have a finely-tuned sense for what their own people want, and will accept.
Both Mr McGuinness and Mr Paisley are personally engaging and are seen as charming and even amusing figures by their own followers - and they've clearly decided that there's no point in going in to this new arrangement half-heartedly.
They must feel that to do so might fuel the sceptism of the doubters who clearly exist in both their communities.
So they have adopted a curious joint persona in public - their relationship has a bantering, indulgent feel to it - indeed at one ceremony welcoming the president of the European Commission, Jose Manuel Barroso, they worked off each other like a well-established comedy double act.
Northern Ireland's voters, who have waited impatiently for their politicians to consolidate the political gains that flowed from the IRA ceasefire 13 years ago, are amazed, but puzzled at the easy chemistry between the two men, which was on display again as they took tea together with Tony Blair and Bertie Ahern.
One man I know whose family suffered terribly during the years of violence said although he was happy that power was now being shared, he felt a sense of frustration that so many people had to die before it came to pass that people who are clearly able to share power, were ready to share power.
Of course, historians and political scientists can give you any number of reasons why this all took so long, but while you are contemplating the subtleties of Northern Ireland's new political architecture, it's worth reflecting that it is built on foundations of pain and loss.