Clans of Ireland Series: The Dal Cais

Hey Clan!

Today I’m kicking off a new series of blog posts focusing on the clans of Ireland featured in my historical fiction saga: Tale of the Clans. This post will focus on the Dal Cais (one of my favorites) but first, there’s something you should know.

Because this series spans the lifetime of Ireland’s infamous high king, Brian Boru, many clans pop up in my novels. As you might imagine, keeping track of them all presents a bit of a challenge.

So to offer you some background before reading the novels, we’ll venture through the Irish clans and give you a little context for the major players you’ll read about, with some tantalizing history on the side.

Map of Ireland - M.N. Stroh Tale of the Clans

Are you ready to get started?

Excellent! So we’ll launch with a fun disclaimer that should gratify the historical purists and provide a lesson for those just learning about Irish history.

The Irish of the 10th century (and indeed centuries before and after) didn’t refer to their family groups as “clans”.

I know! Shocker, right?

Instead, the most common distinctions for kin groups were:

  • Cinel (pronounced Kinnel)
  • Fine (pronounced Finna)

Now, these groups centered around a prominent male descendant who lent them distinction from other kin groups and that distinction broke down and branched out by relation proximity. So you’d have the broad family group: the fine, but then that parceled out further into the flaith-fine, the ceann-fine, the Geilfine, the Deirbhfine, the Iarfine, and the Innfine.

And by now you’re thinking: All these distinctions aren’t so “finna”.

Since the breakdown can be a bit confusing, I fell to agreeing with the decision by later historians to classify the groups with the generalized term “clan”. It seemed the safest resort and best means to insure readers didn’t hurl my books across the room with extreme prejudice.

So throughout this blog series, we’re going to use the terms “clan” and “clans” and I hope you’ll be “finna” with that.

Moving on…

Today we begin our blog series with the star of the Tale of the Clans saga. A clan both as infamous to history as it was obscure in its origins…

The Dal Cais of Thomond

Relief map – Clare (Ireland) – 3D-Rendering by Schwabenblitz. Shutterstock Standard License.

First, let’s break down the name…

Dal Cais, (pronounced: Dăl Căsh) comes from Dál, meaning “portion” or “share” of Cas. Cais refers to Cas mac Tail, grandson of Lughaidh, called Borumha.

Fun fact:

You may recognize two popular surnames from Irish families who can claim descent from the Dal Cais: O’Brian and Kennedy.

Among their own, the Dal Cais considered themselves to be one of two pillars of nobility that maintained rule in Ireland, particularly in the province of Munster (known as Mumhain or Mumu in earlier times). The other family, was the Eoganacht of Cashel.

In ancient Ireland, pedigree played a big part in a clan’s right to rule. Ruling clans often falsified genealogies in order to justify their sovereign lines. The Dal Cais were masters at this game.

In 10th century Ireland, the clans of the Eoganacht traditionally ruled Munster, and they claimed a notorious progenitor named Eogan Mór. The Dal Cais knew a connection to this progenitor was needed in order to justify their right to butt in on Eoganacht dominance. So they forged a connection to Eogan Mór through Cas.

Now, before you get up in arms about the dishonesty of this move, remember, this was a common practice, and the Eoganacht progenitor was just as saturated in myth. In fact, the Eoganacht descended from Conall Corc. But I digress.

The true origins of the Dal Cais start in a clan known as the Deisi Tuisceart (sometimes spelled Deis Tuaiscirt). They were a branch of the Deisi, a subject clan of the Eoganacht who lived in the southernmost regions of Munster. The Deisi Tuisceart eventually migrated to what is present day County Clare.

The first mention of the Dal Cais comes from an annals reference in the year 934 AD, when Rebachan mac Mothlai, the abbot of Tomgraney and King of the Dal Cais, died. He was a compromise candidate between two rival segments of the Dal Cais clan: the Ui Oengusso, and the Ui Thairdelbaig (Thairdelbaig, anglicized Ui Turlough in my novels). While the Ui Oengusso maintained the dominance of the Dal Cais for quite some time, the Ui Turlough were soon to steal their thunder.

More on that later!

Where Did the Dal Cais Live?

Ireland Map Thomond 10th Century - M.N. Stroh

*The area marked in red on the map is not an exact representation of Dal Cais lands but a generalization of their original home territory.

The Dal Cais territory, known in Old Irish as túatha, lay on both sides of the Shannon River from just north of Limerick to Lough Derg. They controlled all the crossings of this massive waterway, which during that time brought them in conflict with another strong power, the Norse who controlled the longphort of Luimnech, situated on King’s Island inside what is now the city of Limerick.

During the Viking era, the Norse ships: longships and other variants, became a key element in the military advancement of Ireland. The Dal Cais, as it turned out, were situated in a power vacuum on that prime piece of real estate, and this put them in the perfect place to exploit that advantage.

Dal Cais Dominance: Where it All Began

While the Ui Oengusso branch strove to maintain rule over the Dal Cais, their craftier sister clan, Ui Turlough, decided to make a power move and entered into a minor marriage alliance with the strong Ui Neill clan in the north. This alliance, brokered by their first notorious leader, Cennedigh mac Lorcan, gave them the advantage.

Cennedigh’s line took the first step in securing dominance over the Dal Cais when his father, Lorcan succeeded as king after the death of Rebachan mac Mothlai in 934. After Lorcan’s death, Cennedigh claimed his father’s throne, and we discover the first reference to him as King of Thomond in the Annals of Ulster in 944 where he suffered a great defeat in Mag Duine at the hands of King Chellachan of Cashel.

Though little is known of Cennedigh’s reign, he showed himself to be both ambitious and prolific. He engaged in battles and raids not only against the Eoganacht and Ui Neill, but against King Ivar of Luimnech, a powerful enemy who had only recently gained dominion over Luimench’s lands after the death of his predecessor, Harald Sitricson, an overlord related to the ruling family of Dublin.  

In 951, a Viking band (called Foreigners by the annalists) raided prominent church lands near the Dal Cais’ realm and brought Cennedigh to his untimely end. During Cennedigh’s lifetime he had twelve sons and an unknown number of daughters. His son, Lachtna, was the first to succeed him, but was assassinated by distant segmentary rivals representing both the Ui Oengusso and the Ui Turlough, who obviously opposed his choice as king.

The assassination failed to subdue Cennedigh’s line, though, and another son, Mathgamhain (anglicized, Mahon), arose to power.

For a time, Mahon and his brothers continued their father’s conflict with the foreigners and any who threatened their realm, but he eventually formed a tenuous peace with Ivar of Luimnech. A peace, Mahon’s younger brother, Brian, opposed to great effect.

The Rise of Brian mac Cennedigh (Brian Boru)

Brian Boru Sculpture Dublin Castle. Original image Shutterstock standard license

A sculpture of an Irish King—Brian Boru, located on the exterior of the Chapel Royal at Dublin Castle in the historic city of Dublin, Republic of Ireland. Original Image by Chris Dorney. Shutterstock Standard License.

According to Cogadh Gaedhel re Gallaibh (‘War of the Irish against the foreigners’), a book largely regarded by historians as propaganda propping up the Dal Cais, Brian mac Cennedigh opposed his brother’s peace agreement. In rebellion he took a secret band of warriors and engaged in guerilla warfare against the foreigners of Luimnech.

Brian’s efforts met with mixed results, as one might imagine. But eventually he won his older brother over, and their combined ambitions led to Mahon’s claim over the kingship of Cashel, which was the seat of Munster’s rule. With the Eoganacht Cashel under Mahon’s authority, the Dal Cais successfully turned sights back on Ivar of Luimnech and came against him in the battle of Sulcoit. An utter defeat for Ivar and his forces, which resulted in the complete sacking and burning of his longphort.

After the success of Sulcoit, Mahon set about establishing his kingship over the province of Munster. Under the cloak of alliance, though, his subdued enemies remained a powerful threat. A plot, designed by Mael Muadh mac Bran, King of Desmond, ended in Mahon’s capture and assassination in 976. The annals accredit Mael Muadh (anglicized Molloy) as king over Munster after that. His dominion proved short-lived.

Mael Muadh likely underestimated the tenacity of Brian mac Cennedigh. In three short years, Brian managed to rally his allies about him and enact vengeance on the conspirators who brought down his brother. All were subdued and slain, Mael Muadh last of all. Each of their families and subject clans brought under Brian’s rule.

Once the kingship of Munster fell into Brian’s grasp, he cut loose a string of strategic battles and alliances which ultimately led to the subjugation of the powerful Ui Neill clans of the north and the Danes of Dublin. By the year 1005, Brian laid claim to the high kingship of Ireland. Though by no means uncontested, Brian succeeded in maintaining dominance over Ireland until his death at the Battle of Clontarf in 1014.

So there you have it! Though this is just a taste of the history behind Tale of the Clans, you can sink your teeth into juicier morsels to come.

Up Next: The Eoganacht of Cashel

To learn more about ancient sites associated with the 10th Century Irish Clans, Get Your Free 7 Digital Tours of Ancient Irish Sites Featured in Tale of the Clans!

Some Primary Sources

Now, I’ve spent the better part of twenty years studying this subject, so to give you a complete list of all my sources would take pages. Though this list is by no means exhaustive, it contains many of the most helpful resources I’ve referenced time and again, along with others which might help springboard further research for any interested in this subject.

An Illustrated History of Ireland by Mary Frances Cusack

Brian Boru and the Battle of Clontarf by Sean Duffy

Brian Boruma, King of Ireland. John Ryan, S.J.

Ireland Before the Normans By Donnchadh O’Corráin

North Munster Studies: Essays in Commemoration of Monsignor Michael Moloney. Edited by: Etienne Rynne. The Thomond Archaeological Society, Limerick, 1967.

On the Manners and Customs of the Ancient Irish, Vol. 1-3. by Eugene O’Curry

The Rise of the Dál Cais. John V. Kelleher

The Annals of Innisfallen

The Annals of the Four Masters 

The Annals of Ulster A.D. 431-1201. 

The Brehon Laws: A Legal Handbook by Laurence Ginnell. 1894.

The Course of Irish History Edited by T.W. Moody & F.X. Martin

The Vikings in Ireland and Beyond: Before and After the Battle of Clontarf Edited by Howard B. Clarke & Ruth Johnson

The War of the Gaedhil with the Gaill

5 Comments Add yours

  1. Brandy B says:

    What a fascinating and complex history. These posts really help me understand the foundation for your books. Thank you.

    1. M.N. Stroh says:

      I’m so glad they’re helpful to you, Brandy! When I first set out to write them, I wasn’t sure whether they would be as helpful to readers who had yet to read my novels. But I hope that I can call attention to them more in the future so that they can be a help to others who might not be aware of them but have read the books.

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