Inside the majestic chamber of Newgrange, one of the most iconic Irish megalith sites.

The European Neolithic era was a time of change. The first agricultural revolution saw people take a stronger interest in farming, small-scale communities grew, polished stone axes cleared forests, and handmade pottery became popular. This was also the period when people built many of the megalithic structures we see dotting the landscape today. A new study reveals secrets about one of the most famous Irish Neolithic monuments – Newgrange – and can teach us more about how it and other Irish megaliths were built.

Were the Irish Megaliths a Product of Cooperation or Dynastic Orders?

Newgrange is a 5,200-year-old passage tomb and part of the impressive Bru na Bóine complex located in County Meath, Ireland. It measures 85 meters (279 ft.) in diameter and 13 meters (43 ft.) in height. Given the extensive labor involved in planning and constructing this and other megalithic sites from the period, one could say that the increasing number of these buildings provides a clear sign of social organization. But there has long been debate about how much of the work going into the great passage tombs was cooperative and how much depended on a hierarchical social system. New analysis of human remains found at Newgrange and other Irish Neolithic sites sheds light on this discussion.

Newgrange, one of the most famous Irish megalith monuments.

Professor Daniel Bradley, co-author of the current study and the Head of Genetics & Microbiology at Trinity College Dublin, told Ancient Origins there were three especially surprising discoveries made when the research team studied the ancient DNA of individuals from “all of the major Irish Neolithic funerary traditions.” These were “The finding of the individual with parents who are first degree relatives in the centre of Newgrange, the finding that there was an individual in the Neolithic who had a great grandparent who was an Irish hunter-gatherer, and the discovery of an infant from Neolithic Poulnabrone who had Down syndrome.” We’ll examine each of these findings in more detail.

Incestuous Relationships and Social Hierarchy

These new findings are revealed in an article titled ‘A dynastic elite in monumental Neolithic society’ which is published in the journal Nature. In their paper, the researchers explain more about the “the adult son of a first-degree incestuous union from remains that were discovered within the most elaborate recess of the Newgrange passage tomb” – a finding which they believe supports the idea of hierarchy being present in Neolithic Ireland.

Elaborate decorations carved into a stone inside the chamber of Newgrange, one of the Irish megalith monuments.

Study co-author Dr. Lara Cassidy, also of Trinity College Dublin said in a press release:

“I’d never seen anything like it. We all inherit two copies of the genome, one from our mother and one from our father; well, this individual’s copies were extremely similar, a tell-tale sign of close inbreeding. In fact, our analyses allowed us to confirm that his parents were first-degree relatives.”

The man’s cranial remains date to roughly 5,000 years ago and were discovered within the most elaborately decorated part of the chamber inside Newgrange in the 1960s during an excavation led by Professor MJ Kelly. While the researchers cannot distinguish through their simulations if he was the child of full siblings or a parent and offspring, they write that either way “the offspring of a first-order incestuous union […] is a near-universal taboo for entwined biological and cultural reasons.”

But as Professor Bradley notes “The prestige of the burial makes this very likely a socially sanctioned union and speaks of a hierarchy so extreme that the only partners worthy of the elite were family members.”

The chamber inside Newgrange.

In the paper, the research team likens this to a “rarely observed phenomenon known as ‘royal’ or ‘dynastic’ incest,” which was practiced in the elite of the Inca empire, ancient Egypt , and pre-contact Hawaii, and was exempt from social rules due to the individuals’ supposed divinity. The nature of their divine status and the desire to legitimate and prove their power has linked these ancient ruling elites around the world with elaborate monumental building projects and extravagant public rituals.

Evidence at Newgrange of a Very Old Legend

Newgrange is recognized as one of Ireland’s most cherished sites and there are many legends surrounding it such as tales of visitations by the Queen of the fairies , magicians, ancient gods , and long-forgotten kings . Some of the most iconic stories are also linked to the solstice alignments witnessed at the site. The researchers highlight a tale that intertwines their new findings with a very ancient oral tradition:

“First recorded in the 11th century AD, four millennia after construction, the story tells of a builder-king who restarted the daily solar cycle by sleeping with his sister. The Middle Irish place name for the neighbouring Dowth passage tomb, Fertae Chuile, is based on this lore and can be translated as ‘Hill of Sin’.”

Sunlight inside Newgrange on the solstice.

As Ros Ó Maoldúin, an archaeologist on the study said in the press release, “Given the world-famous solstice alignments of Brú na Bóinne, the magical solar manipulations in this myth already had scholars questioning how long an oral tradition could survive . To now discover a potential prehistoric precedent for the incestuous aspect is extraordinary.”

More Insight on Neolithic Ireland

In this study, the researchers analyzed 44 whole genomes, which Professor Bradley told Ancient Origins came from “the Ulster Museum, the Duckworth in Cambridge, and mostly from the National Museum of Ireland.” There were more surprising discoveries to be made in the analysis of these ancient genes.

For example, the researchers discovered the earliest known definitive evidence in the world (dated to 3629–3371 BC) for a case of Down’s syndrome in an infant boy who was buried at Poulnabrone portal tomb. The child was buried at the site five and a half thousand years ago and the press release states that this is “an indication that visible difference was not a barrier to prestige burial in the deep past.”

Poulnabrone portal tomb, a dolmen in the Burren, Co Clare, Ireland.

The researchers also found that there were familial ties between some major monumental sites by comparing the genes of the man’s cranium found inside Newgrange with human remains at sites such as Carrowmore, Carrowkeel, and Millin Bay. They write that the four locations together “form a distinct cluster that is split from a larger British and Irish grouping.” Dr. Cassidy notes that this provides more evidence for an elite group in the Neolithic society as “It seems what we have here is a powerful extended kin-group, who had access to elite burial sites in many regions of the island for at least half a millennium.”

In the ‘News & Views’ overview of the Nature article, Alison Sheridan of the Department of Scottish History and Archaeology, National Museums Scotland, points out that “even though they might have ranged widely over Ireland when choosing partners, members of these communities did not sail back to Britain or across to the continent to interact with people there — contrary to what some archaeologists have proposed.”

Farmers From Across the Sea

The study suggests that the Irish megalith builders were farmers who had migrated to the island and then replaced the hunter-gatherers who had been living there. However, there are also indications in this study that the early farmers didn’t eradicate the hunter-gatherers, as Professor Bradley noted before there “was an individual in the Neolithic who had a great grandparent who was an Irish hunter-gatherer.”

Finally, the earliest Irelanders also showed genetic imprints of a prolonged isolation on the island, which fits with the understanding of the area’s geography following the Ice Age. While the region of modern day Britain was still connected to the continent by a land bridge, the island that is now Ireland was separated by sea, meaning some sort of boat would have been needed to reach it.

Overall this study emphasizes that an analysis of ancient genomes can reveal much more than just familial ties, dietary habits, and population movements. By combining this important information with archaeological and historical details, and even ancient myths, we can find clearer indications of what political systems and social values looked like in prehistory.