Mysterious man on a creepy night. Who really killed the King?

Who Killed the King? An Ancient Irish Murder Mystery


It might almost be a shocking moment from a Shakespeare play or even a plot-line from Game of Thrones, but the murder of an ancient Irish king, Crimthann mac Énnai, is an event which actually took place over 1500 years ago.

Most sources state that it was Crimthann’s grandson, the unsubtly-named ‘Eochaid the Slayer’ who carried out the deed, but there is the possibility that there was another who had more reason to seek Crimthann’s death.

This is an ancient Irish murder-mystery with familial and tribal intrigues — a dramatic yet often overlooked moment in Ireland’s past.

An illustration of two axe-wielding Irishmen from Royal MS 13 B VIII (Topographia Hibernica).

An illustration of two axe-wielding Irishmen from Royal MS 13 B VIII (Topographia Hibernica). ( Public Domain )

The Sacred Tree

Crimthann mac Énnai was a king of the Irish province of Leinster who reigned from 443 AD to 483 AD. His residence was located in Rathvilly, which today is part of County Carlow, but at this time it was a tribal territory, as county borders had yet to be established in Ireland.

Rathvilly translates as ‘Ringfort of the Sacred Tree’ and this description gives tantalizing clues as to Rathvilly’s forgotten prominence as a place of worship and site of power for Ireland’s Druids and potentially the Irish people who lived there thousands of years earlier. The sacred tree in this case is most likely the oak but other trees which were considered gateways to the spiritual realms for the ancient Irish include the ash, the yew and hawthorn.

Ancient Oak Tree, Fowlet Farm, Hollybush.

Ancient Oak Tree, Fowlet Farm, Hollybush. (Jerry Fryman/ CC BY-SA 2.0 )

Rathvilly is surrounded by many historic and sacred monuments including dolmens and stone circles which have alignments to solstices, equinoxes and even the stars.

Who Built the Homes of Gods and Kings?

Although these sites were held sacred by the Druids and the Celtic and European people arriving in Ireland at this time, their builder’s origins are still shrouded in mystery. For many who read Celtic legends today, these sites are the locations and homes of the Kings, Queens, Gods and Goddesses of Irish mythology - but it is worth restating that these places were in fact rediscovered by the Celts , and not built by them.

Recent DNA evidence has found that some people living in Ireland when these sacred monuments were built were from the Fertile Crescent area. However, there is also evidence that people from Northern and Eastern Europe were travelling to Ireland at this time as well. Perhaps the facts are pointing us towards a scenario of a mixture of races and cultures that traded, shared the same land, and called the same gods by different names. Archaeology continues to reveal new information which makes any definitive statement shaky ground. Irish legends even speak of a mysterious people called the Tuatha Dé (The Tribe of the Gods) who were said to possess supernatural powers and who arrived in Ireland in ‘dark clouds’.

The Tuatha Dé (The Tribe of the Gods) were said to arrive in dark clouds

The Tuatha Dé (The Tribe of the Gods) were said to arrive in dark clouds. ( Public Domain )

With this in mind, Crimthann mac Énnai would have inherited great power presiding over a territory containing such important local ceremonial and ancestral monuments such as Baltinglass Hill and Castleruddery stone circle.

Castleruddery Stone Circle (© David Halpin)

Castleruddery Stone Circle. (© David Halpin)

Death by Werewolf and Shape-Shifting Cannibals

Ireland’s landscape at this time was thickly forested and home to other powerful chieftains and tribes. It was also a time when packs of wolves roamed and stalked the whole of Ireland. Settlements were reinforced and guarded, not just to repel attacks from rival tribes but to also protect against the wolves.

The fear instilled by these creatures informed many Irish myths and beliefs, from werewolves to shape shifting cannibals. Traveling by day was a dangerous undertaking; traveling at night would have been perilous. Kings not only held the power to rule, but the power to banish. Being cast outside of protective territory would have been a terrifying and potentially fatal outcome for individuals and whole families. It is worth bearing this in mind when we look for potential reason for Crimthann’s murder.

Being out in the dark woods was dangerous territory

Being out in the dark woods was dangerous territory. ( Public Domain )

New Religion and Shifting Alliances

This was also the time when Christianity began arriving in Ireland and some local accounts even say that Crimthann met, and was baptized by, St. Patrick . An ancient pagan holy well in Rathvilly was later named after Ireland’s patron saint in honor of this legendary event. The politics and power of this ‘new’ religion and its influence upon kings and tribes is yet another factor which began to change alliances in Ireland at this time.

The background leading to Crimthann’s death is recorded in the Annals of Ulster, The Annals of the Four Masters and the Chronicum Scortorum.

These circumstances become less clear because of the various genealogies which seem to share some details but differ on others.

Eochaid the Slayer – Convenient Patsy?

It seems that Crimthann had a succession of wives, including three sisters, and it was the second of these, Ingren, who gave birth to the child who would go on to be the main suspect in Crimthann’s death in one version of events. This grandson’s name was Eochaid Guinech—or as he became known, ‘Eochaid the Slayer’ .

However, yet another ancient source, Tripartite Life of St. Patrick , claims it was not Eochaid who slew Crimthann but Eochaid’s father, Oengus. According to this version of events, Crimthann had banished a tribe called The Sons of Mac Ercae which had been led by Oengus’s father. It seems that the motivation to seek Crimthann’s death was to avenge this banishment. As we have mentioned, banishment was not merely an inconvenient vanquishing to another part of the country but was more likely to be a death sentence upon a whole extended tribe or family by robbers, rival tribes, and not least the wolves.

Banishment risked tangling with robbers, rival tribes, and wolves.

Banishment risked tangling with robbers, rival tribes, and wolves. ( Public Domain )

Means, Motive, Opportunity

With different interpretations and so many centuries having passed, it is hard to know exactly how these events really unfolded. What we do know is that Crimthann was slain on the battlefield and most sources state that it was his grandson who murdered him. But the suggestion and recording of another suspect with clear motives for wanting Crimthann dead means we must leave room for doubt.

Perhaps Oengus did in fact kill Crimthann, as some texts say. Or perhaps he decided that it would benefit the transition of his family’s rule in order to encourage the savage reputation of his son, Eochaid. The legacy of Eochaid’s nickname, Eochaid the Slayer, is testimony to the fact that this was what most people believed.

Rathvilly Moat, County Carlow, Ireland. (© David Halpin)

Rathvilly Moat, County Carlow, Ireland. (© David Halpin)

Today, Rathvilly moat still stands as a reminder of Crimthann’s rule. From its summit, nine different counties can be seen on a clear day. Perhaps, in time, new records will be discovered which will allow us to re-examine Crimthann’s fate with the same clarity.

A view from the summit of Rathvilly moat. (© David Halpin)

A view from the summit of Rathvilly moat. (© David Halpin)

David Halpin © September 2017 

David Halpin is a writer from Carlow, Ireland. He compiles local folklore and documents alignments between ancient monuments near his home in Ireland, and is a regular contributor to Ancient Origins and various Fortean and occult websites. Join him for virtual and physical guided tours of ancient Irish sites at @CircleStoriesDavidHalpin


Top Image: Mysterious man on a creepy night. Who really killed the King? (Public Domain;Deriv)

By David Halpin

Updated on October 26, 2021.


Koch, John T. Celtic Culture: A Historical Encyclopaedia. ABC-CLIO, 2006. pp.1693-1695

Carey, John (Winter 2002). "Werewolves in Ireland". Cambrian Medieval Celtic Studies (44): 37–72.

Stokes, Whitley, ed. and tr. (1887). The Tripartite Life of Patrick: With Other Documents Relating to that Saint. London.

“Archaeological Inventory of County Carlow”. Page 78. Dublin 1993

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