A 5th century Irish warlord known as Niall of the Nine Hostages may literally be the father of his country, says a genetic survey, which shows he has as many as 3 million direct male descendants.

At least one in every 12 Irishmen worldwide and one in every five in the northwest of the island of Ireland, Niall’s stronghold, carry a genetic marker on their Y chromosome that can be traced back to a single individual, geneticist Daniel Bradley and his colleagues at Trinity College in Dublin, Ireland, reported this week in the American Journal of Human Genetics.

Niall, a near-mythical figure, got his name by taking hostages in raids on other important clans in Ireland, Britain and France to cement his hold on power. He is reported to have had 12 sons, which was not uncommon for medieval leaders.

His descendants, known as the Ui Neill, apparently maintained their dynasty long enough for the bloodline to become firmly entrenched in the Irish genetic heritage, ruling until the 11th century.


Niall may have an impressive legacy, but he was a piker compared with Genghis Khan, whose descendants throughout Asia are thought to total about 16 million.

But the Irish lord edges out Giocangga, founder of China’s Manchu dynasty, who is thought to have 1.6 million descendants.

The Y, or sex, chromosome, is passed down from father to son unchanged and is thus widely used as a marker to trace genetic inheritance.

The team found that the marker was most common in men whose surnames have been traditionally linked to the Ui Neill dynasty, including O’Neill, O’Connor, O’Donnell, O’Reilly, Flynn, McGovern, McManus, Molloy and O’Rourke.