Royal incest is always going to grab the headlines. And so it proved last week when a fascinating study was published in Nature revealing the results of a project, whose first author is Dr Lara Cassidy at Trinity College Dublin, sampling human bone remains from Neolithic Irish sites.


The most eye-catching of several interesting results came from analysis of an adult male, whose cranial remains were found inside the famous 5,000-year-old Newgrange passage grave in Brú na Bóinne, the world heritage site in Ireland's Boyne valley. His genome indicated that he was “the offspring of a first-order incestuous union” (born to parents who were either siblings, or parent and offspring). The bones of this individual were found in what is assumed to be a prestigious position in the inner chamber of the Newgrange monument.

Dr Cassidy and her co-authors observed that sibling-to-sibling incest has been recorded among elites in other societies (including the Inca Empire and ancient Egypt), and that “this behaviour co-occurs with the deification of political leaders and is typically limited to ruling families”. Thus the headline of the story in the Daily Mail began “Ireland's ancient kings married their sisters and fathered inbred children to maintain dynastic bloodlines”.

Medieval mythology

That is a pretty newsworthy story in itself, but in addition, Dr Cassidy and her team also noted that:

“The Brú na Bóinne passage tombs appear in medieval mythology that relates their construction to magical manipulations of the solar cycle by a tribe of gods, which has led to unresolved speculation about the durability of oral traditions across millennia. Although such longevity seems unlikely, our results strongly resonate with mythology that was first recorded in the 11th century, in which a builder-king restarts the daily solar cycle by copulating with his sister. Fertae Chuile, a Middle Irish placename for the Dowth passage tomb (which neighbours Newgrange), is based on this lore, and can be translated as ‘Hill of Sin’ or ‘Hill of Incest’.”

I've been in touch with Dr Cassidy, and she additionally notes:

“As we are clear in our paper, it is always going to be controversial when you suggest oral longevity across millennia. However, it is not unprecedented. Some Indo-European fairytales are estimated to be 2,500-6,000 years old. Aboriginal Australians have stories of exploding mountains concerning volcanoes that haven't erupted for thousands of years. Importantly, there was already a prior discussion of this myth in this context and it is entirely reasonable for us to add our result to this. Note we make no strong conclusion in this regard.”

Stories to explain places

Nonetheless, that apparent piece of documentary corroboration from medieval mythology drew some criticism on social media from Dr Elizabeth Boyle, Head of the Department of Early Irish at Maynooth University. The story in question here is found in the Metrical Dindshenchas, a compilation of stories that dates to the 11th century AD concerned with the origins of place-names in the Irish landscape. Composed by learned scholars within a Christian context, these stories look back to pre-Christian times to explain how places got their names. I called Dr Boyle to find out about her reservations about the usefulness of this source to the argument in the paper.

“This is the story of the placename Dowth, one of the three Neolithic monuments in Brú na Bóinne [along with Newgrange and Knowth]. In Old Irish, the place-name Dowth is dubad, which would literally mean ‘darkness’. The story says that the king of Ireland at that time is called Bresal. In his reign Ireland is struck down by a cattle murrain [disease], and the cattle die. So everyone gathers at the court of the king and they decide that they are going to build a tower to heaven, like the Tower of Babel [the Old Testament origin story in the Book of Genesis]. Presumably the aim is to ask God to stop killing the cattle. They decide that they will spend the length of one day building this tower up to heaven. And they start building. The king's sister is a sorceress. And she's going to create some magic in order to stop the sun from moving so that the day will last long enough for them to build the tower.

"The story says that she goes off somewhere to do her magic. And her brother follows her. He has sex with her, and because she's now committed incest, her magic fails. And the place where they're building falls into darkness. And so it is called dubad. Further, we're told that wherever they went to go and have sex with each other, that place gets called Fertae Chuile, the burial mound of sin or the burial mound of violation or incest. And that's what they're seizing on in the article, that wherever the brother and sister have sex in the narrative is called the burial mound or the mound of sin or incest. But, as I say, it explicitly says in the story that they are trying to build a new Tower of Babel. They're trying to build a tower to heaven. And so that even in itself is enough to say that this isn't a story that goes back to the Neolithic period because it's borrowing directly from the Bible. And in any case, it's not clear where this place, Fertae Chuile, is located, because wherever they're having sex, it's not in Dowth itself, because that is where the tower was.”

So, given that the story in question here appears to be derived from Biblical stories, it’s unlikely, in the view of Dr Boyle, to correlate with any sort of cultural practices that may or may not have been ongoing in the Neolithic, several millennia previously. Whatever fascinating cultural practices are implied by the scientific analysis, an early medieval literary source, composed within a Christian milieu, does not add weight to the argument. The problem is compounded by the actual language used in the source in question.

“The key thing that wound me up about the article is that the people who built Newgrange and built those nearby monuments were not Celtic-speaking people. The Celtic language and Celtic-speaking peoples were only introduced into Ireland probably in the early Iron Age, maybe around 500 BC, so thousands of years after Newgrange was built,” notes Dr Boyle. “Almost all of the place names in Ireland in the Old and Middle Irish periods are clearly identifiable as Irish place names. Every place name in Ireland had therefore been renamed since the Neolithic period in the Celtic-speaking period because the place names are all in a different language: they are all in Irish. There were no Celtic-speakers on the island of Ireland when Newgrange was being built. I think it's improbable enough to have something like a folk memory that lasts for four thousand years, but it would also have to last across a language change, the introduction of a new culture into Ireland, and this very clear renaming of the Irish landscape, because all of these place names in the Dindshenchas are Irish place names and not whatever language preceded Irish in Ireland.”

A fuzzy, vague Celtic past

So, if the Dindshenchas do not provide a viable witness to Neolithic practices, why do they get employed here? “For me, it’s flagging up a problem with perceptions of Irish history, where everything prior to the arrival of the Normans in the 12th century is often seen as some fuzzy, vague Celtic past where it's all the same,” comments Dr Boyle. “And it doesn't matter if it was something built in 4000 BC or something written in AD 1100, it's all perceived as being kind of the same.

She continues:

"But there is so much radical social transformation continually underway in Ireland. There are technological developments. There are language shifts and language changes. There is conversion to Christianity. There is introduction of literacy. A lot has changed in that period. This misconception reflects, I think, a wider perception that Ireland doesn't really have any ‘history’ until the English turn up and everything else before that is just some vague, ahistorical, stuff about druids and warriors.”

This isn’t to say that the people alive in the 11th century AD weren’t interested in these prehistoric monuments, as shown by the very documentary sources that we’re talking about here. “In medieval Ireland there is a very complex awareness of landscape as a whole, both manmade features on the landscape and the natural landscape in general. And this is reflected in the Metrical Dindshenchas,” suggests Dr Boyle.

“This is a genre of learned literature, but it’s a very dynamic tradition and you can see them creating new stories for places that are interacting with the landscape. They know that these monuments are incredibly old. They don't have any connection with the Neolithic culture that built them. But they know that this is something the construction of which could be projected into their prehistory. Oftentimes they're not projecting it that far into prehistory. To take an example of one Neolithic tomb at Knocknarea, the story around it is that it's the tomb of a queen, Maeve (Medb), who is depicted in literature as having lived maybe only about a thousand years before they are writing, when actually the tombs themselves are about 5,000 years old. So they're projecting them back into a past, but not a past that's as old as the monuments actually are.”

Whose afraid of the prehistoric past?

We ran a feature on this site on Anglo-Saxon fear of prehistoric barrows and I've blogged previously about early medieval attitudes to prehistory. Thinking about all this did remind me of the work of Professor Sarah Semple at the University of Durham, who has done much work on changing perceptions of the prehistoric in early medieval society before and after the conversion to Christianity.

For example, in a paper in the journal World Archaeology in 1998, Professor Semple noted that:

“The late Anglo-Saxon attitude to prehistoric barrows was one of superstitious wariness; emotions also connected with boundaries. Both places were portrayed as the haunt of monsters, spirits and evil creatures in the eighth century and after. The poetic sources are the product of a Christian world and represent a Christian perception of the landscape. The root of this perception may be the remembrance of early Anglo- Saxon pagan activity which took place at barrows.”

Now, of course, I wanted to check in with Dr Cassidy to get her take on Dr Boyle's thoughts. She replied as follows:

“I need to stress that the mythology did not feed into our conclusions on the political form of these societies. That was based on the son of a first degree union interred within one of the most prestigious burial structures known for prehistoric Europe, the long distance patterns of relatedness with other passage tomb sites, the diet and the material culture of passage tomb cemeteries, which shows high investment in public ritual and monumentalism.

“It is well accepted that biblical narratives and local pagan mythology were woven together in works like the Dindshenchas. Untangling the two is a complex task. I would avoid speaking in certainties about it and we were sure not to in the paper. Unfortunately, we can't control the tabloids.”

The Celtic question

With regards to the question of language, Dr Cassidy has this to say:

“Our team is very aware that Ireland has undergone radical transformation since the Neolithic. In fact, in 2016 we were the first to demonstrate a transformative population migration to the island in the Early Bronze Age (~2,200 BC). Another result in that paper challenged the outdated paradigm that Dr Boyle repeats 'Iron Age Celtic-speaking people arrived in Ireland 500 BC'. There has never been any substantial archaeological evidence for this transition and there is also no current genetic evidence.

“In fact, we see very strong genetic continuity between the modern Irish people and the Early Bronze Age population. This feeds into a growing body of work called "Celtic from the West" (a set of volumes by Barry Cunliffe and John T. Koch), which argues that precursors to Celtic arose in the Late Bronze Age across Atlantic sea networks from an Indo-European substratum [this is a topic explored by Professor Barry Cunliffe on this site]. Indo-European languages are now widely believed to have been introduced to western Europe by the continent-wide migrations in the Late Neolithic/Early Bronze Age. although a small contingent argue that they were already there in the Neolithic. I would advocate the former, but the debate is not fully closed. Either way, it is very probable that some form of Celtic Language was in Ireland long before the Iron Age imaginings of romanticists in the late 19th and early 20th century.

“The next phase of our research will actually be focussed on the Neolithic to Bronze Age transition in Ireland and how these two different peoples consolidated with one another over time with respect to their genes and cultures. For example, we see continued use of older megalithic sites and the construction of a new megalithic tomb type (wedge tombs) for many centuries after the end of the Neolithic. There is potential at this interface for the exchange of folklore.”

The question of how far back you can project values or attitudes from early medieval documentary sources onto prehistoric societies is no doubt one that will continue to drive debate. Dr Boyle has one last comment, for now, on the question of language: “I reject the idea that the Celtic language arriving in Ireland c500-c.100 BC is ‘outdated’. Rather, it represents the best accepted consensus of the situation on the part of experts in the history of the Irish language and the ‘Celtic from the West’ model is at best a fringe opinion.”

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Linking literature and science

Finally, although Dr Boyle did note on Twitter that “if a medievalist had cast their eye over the paper pre-publication, this unfortunate methodological error could have been avoided”, she did conclude to me by saying “I'm not blaming the scientists. Science-wise, it’s a really good paper. It's a really important paper telling us all sorts of things about the Neolithic period. I just don't think 11th-century Irish literature tells us anything about the prehistoric period.”

So, clearly this conversation has some way to run. I’ll leave the last word on it for now to Dr Cassidy:

“Overall, my take home would be that the question of oral and linguistic continuity in Ireland is very much an open one. It will require an interdisciplinary effort to address. In that spirit, it would have been remiss of us not to highlight a potential new piece of evidence in the paper, especially given the previous speculation regards Brú na Bóinne itself. We did not start the debate and I do not believe it is anywhere near finished! It's an exciting time to be in the field. Dr. Boyle's point about a 'fuzzy Celtic past' is very apt, with ancient genomes we are hoping to do some defuzzing!”


David Musgrove is content director at HistoryExtra. He tweets @DJMusgrove. If you've got any subjects you'd like him to try to defuzz in this blog, drop him a tweet to tell him what he should cover. Read the latest in his medieval matters blog series here


Dr David MusgroveContent director,

David Musgrove is content director of the website and podcast, plus its sister print magazines BBC History Magazine and BBC History Revealed. He has a PhD in medieval landscape archaeology and is a fellow of the Royal Historical Society.