Introduction to Brehon Law

What is Brehon Law?

Brehon Law is the law system that Ireland used up until around 400 years ago when the final nail was put in its coffin with the Flight of the Earls.

It worked quite differently to the law system we use today. It has been described as tribal, rural, hierarchical and familiar – meaning a society in which family, not the individual, is the unit. The family being the unit meant that kinsmen were very much interested in what their kin were up to. If they were doing anything that would increase/decrease their honour, they wanted to know about it.

And when I say “honour” I don’t mean the abstract idea of it. Honour was very, very important. And it was measured.


At one point there would have been about 150 Kings throughout Ireland at any given date between 5th and 12th Century. Each of these ran their kingdoms and these kingdoms were known in the law texts as a Túath (Too-ah). Each citizen within a túath had rights. Outside of their túath, they had close to none. To seek justice for a wrong committed against you outside of your túath was next to pointless. For this reason, people spent most of their lives within their túath except to go on pilgrimages, to go to war and to attend óenachs (“Oh-en-ack”- events/festivals held by Kings with an invite to surrounding túaths).

Kings could strike deals with each other and thereby extend the law of their túath to each other. These were known as “Cairde” (Car-dje). I.e. If I visit a túath that my King has a Cairde with, and I get assaulted by someone there, I can seek repayment for this crime the same way I could if it happened in my own túath.

People of one túath could also extend “Protection” to someone of another túath. So, say I have a friend who lives in a túath quite a bit away and I want to go and visit him. I have to travel through lands where I have no rights. It is in my interest to secure protection while travelling through these lands, and the land of my friend.

Protection works by way that if, say, I have given my protection to you while you’re in my túath, and you get mugged/assaulted. The guilty party must now repay me for the crime against my honour. Basically, I have extended my legal rights to include you. You are an extension of me under the law for the duration of the protection. The higher your rank in society, the longer you can extend your protection over someone. Like a modern day visa.

Honour Price

Honour is measured. It has a very real currency. The four main currencies are Cumals (Female Slaves), Silver, Milch Cows and Séts (A measure of jewels and metals). The rough breakdown for the conversion is as follows:

1 Ounce Silver       = 1 Milch Cow
1 Cumal                    = 3 Milch Cows
2 Séts                       = 1 Milch Cow

For the sake of uniformity in this article I’ll just use the Milch Cow as currency.

If I have been proven guilty of wrong-doing against someone else in my túath, I will have to repay them for my crime. This will come in the form of a percentage of their honour price. The more severe my crime against them, the more severe the payment.

Say, for example, for some reason, I assaulted a man on the street. A brethem (judge) is brought in to investigate and hear both sides of the story and speak to witnesses. He then makes a judgement and finds me guilty of assault. The man I assaulted is, let’s say, the local silversmith. He has an honour-price according to his rank in society and, being a silversmith, his honour-price is three and a half Milch Cows (which is a lot). Now, depending on the damage I caused him and the reasons leading up to the assault, the brethem will choose what percentage of the silversmith’s honour price I have to pay.

Failing to comply with the judgement and payment will lead to reduction of my own honour-price and rank in society to the point where I can be reduced to having no rights at all.


Proper judgement is held to be the most important job on the shoulders of a King. To give a false judgement is as unacceptable as fleeing from battle and would reduce a King to the status of a commoner. This can be seen in the story of Cormac Mac Airt’s judgement on the trespassing sheep.

As a young man he was approaching the gates of Tara for the first time, when he saw the steward of King Mac Con telling a woman something which caused her to weep. He enquired what was wrong, and was told that the woman’s sheep had broken into the queen’s woad-garden and had eaten the leaves off the plants. Mac Con had passed judgement that the woman’s sheep be forfeit for this offence, and this was the cause of her distress.

Cormac immediately pointed out to the steward that the judgement should have been ‘one shearing for another’ i.e. the woman should only have to forfeit the shearings of her sheep in recompense for their shearing of the woad-plants. When Mac Con was told of this judgement he immediately realised that he had been guilty of injustice, and handed over the kingship of Tara to Cormac.

This tale serves to illustrate the enormous importance that the early Irish attached to the concept of Fír Flathemon (King’s Justice).

Honour Prices


Here is a small chart listing the professions and the honour-price that they carry with them. Missing from this list is the main body of people that would make up a túath, the “Clients”. Clients would rent a Lords’ land. They are left off this list due to not having a fixed honour-price. Clients were of vastly different status ranging from lowly people, almost unfree, to much wealthier clients who rented larger plots of land and owned much of their own land too.

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