Local historians and genealogists in Wexford have discovered evidence to suggest that President George W. Bush is a direct descendant of Strongbow, the nobleman who led the Norman invasion of Ireland.
The president is also believed to be a direct descendant, through 30 generations, of Dermot McMorrough, the King of Leinster, reviled in many Irish history books as the man who betrayed his island for personal gain.
During his first presidential election campaign in 2000, genealogists discovered a direct link between Mr Bush and prominent Norman families in medieval England.
However, in the last month volunteers working on a tapestry of Ireland's Norman heritage discovered a further link with two of the most notorious figures in Irish history.
It had already been established that Mr Bush had one of the most distinguished New England family histories that could be traced back to the first English in America.
One of his ancestors was Anne Marbury Hutchinson, a famous religious non-conformist who arrived in America in 1634 with the Rev John Lothrop's group on the ship Griffin and settled in Boston. She was killed by Indians in 1643.
Hutchinson herself was a direct descendant of some of the most notable Norman families and figures of the 12th and 13th centuries, including Gilbert "the Red" le Clare, the Earl of Hertford. This was well documented as Gilbert the Red had married Joan of England, the daughter of King Edward 1st.
He in turn was the great grandson of Strongbow, Richard de la Clare, the Earl of Pembroke.
Strongbow famously landed in Bannow Bay, Co Wexford, in 1169, at the request of Dermot McMurrough, the King of Leinster, then embroiled in a bitter conflict with neighbouring kings.
With an army of 100 knights and 1,000 archers, he took much of Leinster, including Dublin, and consolidated his power through marriage to McMurrough's daughter, Aoife.
His arrival heralded the beginning of the Norman invasion.
The link between Strongbow and President Bush was discovered by Ann Griffin Bernstorff, who is working on the Tapestry of Ros, an ambitious project to tell the story of Ireland's Norman heritage.
She was researching the history of William Marshal, Strongbow's son-in-law and effective successor in Leinster, who founded the town of New Ross.
"It's all very intriguing really. We had heard rumours that it was a possibility," she said. "Then one of our committee members had a Republican friend in Chicago. We got the genealogy chart from there and made the link to the de Clare family."
The group does not believe President Bush is aware of his famous ancestor, after it made inquiries with the US embassy in Dublin. Officials told Ann Griffin Bernstorff they had no knowledge of any link with Ireland.
While a direct descendant, Ann Griffin Bernstorff does not believe Mr Bush to have any solid claim on the kingdom of Leinster, as the McMurrough line continues to this day through the McMurrough Kavanaghs in Borris, Co Carlow.
The president should be proud of his Irish roots, Ann Griffin Bernstorff said. "It's an ancient Irish family, one of the oldest on the island, stretching back through the mists of time."