There are stories about Ireland that only DNA can tell, and these are stories about her sons and daughters, a people’s history of migrations and beginnings, of deep ancestry lost in the darkness of the past. It is a different sort of history, not the usual identity parade of the usual suspects; kings, queens, warriors, poets and saints. But as with much in Ireland, it turns out that there is a paradox rumbling around inside that approach to a shared past. The shadowy dynasties of Celtic kings and their feisty queens are more than usually important - to the DNA of ordinary people. Prof. Dan Bradley of Trinity College has likened the discovery of DNA markers, what identifies distinct lineages, to postcards from the past. But in the case of Irish men in particular, these postcards often carry a stamp with a chiefly head on it.

In the past powerful men expected to have a great deal of sex with many different women, a prerogative that hasn’t entirely disappeared. Pre-Christian (and sometimes post) Irish kings were often polygamous and had a commendably relaxed attitude to issues of legitimacy. Perhaps the most spectacular royal progenitor was Niall Noigiallach, the first High King and a figure on the half-lit edges of recorded history. He reigned towards the end of the 5th century, his power lay around Donegal but his genetic reach extends far further. Around 20% of all Irish men share close ancestry with Niall and the frequency of the Ui Neill marker, M222, is highest in the north and much less in the south. It follows that Niall’s children walk the streets of the cities of the USA, Canada and wherever else the great Irish diaspora settled. Their surnames are likely to match their DNA marker; O’Rourkes, O’Connors, MacLoughlins and O’Donnells may well be the sons of Niall Noigiallach. His name means Niall of the Nine Hostages, and these many thousands of descendants all over the world are his hostages to the future, battalions of princes of the Ui Neill.

To find out where you fit into this fascinating picture, go to