A key account of a battle which came to define Irish identity may have been fabricated, a researcher has claimed as the country marks the millennium of the Battle of Clontarf.
Widely accepted accounts of the Battle of Clontarf - a defining moment in Irish history which was fought on April 23 1014 - was partly a "pseudo-history" borrowed from the tale of Troy, according to academics from the University of Cambridge.
In popular history, the battle has been characterised as an epic and violent clash between the army of the Christian Irish High King, Brian Boru, and a combined force led by the rebel king and leader of the Dublin-based Vikings.
The disputed outcome saw the Vikings beaten off, but at huge cost. Brian himself was killed, and became a heroic figure and Irish martyr.
According to Maire Ni Mhaonaigh, from St John's College, much of what we know about Clontarf may be rooted not in historical fact, but a brilliant work of historical literature which modelled sections of its text on an earlier account of the siege of Troy.
Rather than a trustworthy description of the battle itself, this account - Cogadh Gaedhel re Gallaibh or The War Of The Irish Against The Foreigners - was really a work of fiction aiming to cement Ireland's legendary past in the context of a grand, classical tradition, stretching back to the works of Homer and classical philosophy.
It means that despite the widespread portrayal of Clontarf as a heroic conflict in which the lives of Brian and others were sacrificed in the Irish cause, the historical truth is unknown.
While the advent of the battle itself and its significance is beyond doubt, the details of what happened are likely to remain a mystery, Dr Ni Mhaonaigh claims in her new book Classical Literature and Learning in Medieval Irish Narrative.
She added: "The casting of Clontarf as a national struggle in which the aged, holy Brian was martyred still defines what most people know about the battle, and it has probably endured because that was what numerous generations of Irish men and women wanted to read.
"Academics have long accepted that Cogadh couldn't be taken as reliable evidence but that hasn't stopped some of them from continuing to draw on it to portray the encounter.
"What this research shows is that its account of the battle was crafted, at least in part, to create a version of events that was the equivalent of Troy.
"This was more than a literary flourish, it was a work of a superb, sophisticated and learned author."
No archaeological remains have been found, and the precise location, presumed to be somewhere around the modern Dublin suburb of Clontarf, is disputed.
Compared with the very basic information in contemporary chronicles, Cogadh provides by far the most comprehensive account of what happened.
It was, however, written about a century later, probably at the behest of Brian's great-grandson.
Through a close study of the text, Dr Ni Mhaonaigh found that the imagery, terminology and ideas draw inspiration from a range of earlier sources - in particular Togail Troi (The Destruction of Troy), an eleventh-century translation of a fifth-century account of the battle for Troy.
In particular, the unknown author explicitly cast Brian's son, who it is believed led a large part of his father's army at Clontarf, as an Irish Hector, whom he describes as "the last man who had true valour in Ireland".
Rather than pouring cold water on the millennial celebrations by showing the main account of Clontarf to have been an elaborate piece of story-telling, however, the study points out that the work bears witness to the cultural achievements of Brian's successors.
"Whoever wrote this was operating as part of larger, learned European tradition," Dr Ni Mhaonaigh added.
"People should not see the fact that it is a fabricated narrative as somehow a slur against Brian, because what it really shows is that his descendants were operating at a cultural level of the highest complexity and order."