When they had expelled the Tuatha De Danann, and brought Ireland under their own sway, Eibhear and Eireamhon divided the country between them; and, according to some historians, the division made between them was this: Eireamhon to have the northern half from the Boyne and from the Srubh Broin northwards, and Eibhear from the same boundary southwards to Tonn Cliodhna. Thus does the seancha speak of this division -- "Eireamhon and noble Eibhear" is the beginning of the poem:
On the northern side, an event without sorrow,
Eireamhon took sovereignty
From the Srubh Broin, noble the division,
Over every tribe to Boyne.
Eibhear, the prosperous son of Milidh,
Possessed the excellent southern half
He obtained from the Boyne, strong the division,
To the wave of Geanann's daughter.
Now, five of the principal leaders of the host of the sons of Milidh went with Eireamhon to his division, and received territory from him; and each of them built a stronghold in his own portion of the territory. The five leaders who went with Eireamhon are Aimhirgin, Goistean, Seadgha, Sobhairce, and Suirghe. Here follow the royal forts that Were built by Eireamhon and by his five leaders. In the first place he himself built Raith Beitheach in Airgeadros, on the brink of the Feoir in Osruighe. Then Aimhirgin built Turloch of Innbhear Mor; Sobhairce built Dun Sobhairce; Seadgha built Dun Deilginse in the territory of Cuala; Gostean built Cathair Nair; Suirghe built Dun Eadair.
The following are the five who went with Eibhear, namely, Caicher, Manntan, En, Oige, and Fulman, and each of them similarly built a fort. First, Eibhear himself built Raith Eoamhain, in Laigheanmhagh; Caicher built Dun Inn, in the west of Ireland; Manntan built the stronghold of Carraig Bladhruidhe; En son of Oige built the fort of Ard Suird, and Fulman the fort of Carraig Feadha.
From Eibhear to Adam there were thirty-five generations, as the poet says:
With good upbringing, fifteen
And twenty generations,
The tribe of brave men lavish of herds
Up from Eibhear to Adam.
Other seanchas are of opinion that the division of Ireland made by Eibhear and Eireamhon was this: Eibhear to have the two provinces of Munster; Eireamhon the province of Connaught and the province of Leinster; and Eibhear son of Ir, son of Milidh, and others of the leaders who came with the sons of Milidh, to have the province of Ulster; and the cantred of Corca Laighdhe, in south Munster, they gave to Lughaidh son of Ioth, the son of their grandfather's brother. This opinion I am the more disposed to accept as true, as it was in Leinster that Eireamhon's chief stronghold was situated, namely, Raith Beitheach in Airgeadros beside the Feoir, and also because the descendants of Eibhear originally settled in Munster, the descendants of Eireamhon in Connaught and Leinster, and the descendants of Rudhruidhe son of Sithrighe, who sprang from Eibhear son of Ir, son of Milidh, in Ulster. It is from this Rudhruidhe that the name Clann Rudhruidhe is given to the real Ultonians, and to every section of their descendants who went into each other's provinces to seize upon land and to make conquests, such as the coming of the children of Rudhruidhe to Leinster to wit, the descendants of Conall Cearnach to Laoighis, and the descendants of Fearghus son of Rogh to Conmhaicne of Connaught, and to Corca Moruadh and Ciarraidhe in Munster and the family of Duibhidhir of the race of Cairbre Cluitheachar son of Cuchorb of the progeny of Labhraidh Loingseach, and the family of Rian of the race of Cathaoir Mor, who came from Leinster to Munster. It was long after this division which Eibhear and Eireamhon made of Ireland that these tribes went from their own territories into other districts in Ireland. It is also well known that it was in the time of Muireadhach Tireach that the three Collas with their kinsmen left Connaught to win conquests from the Ultonians, and wrested by force from them a large portion of the province of Ulster, namely, Modhairn, Ui Mac Uais and Ui Chriomhthainn; and many of their descendants hold possession of these to-day, as Raghnall son of Samhairle, Earl of Antrim, or Aondrom, descended from Colla Uais; Mag Uidhir, Mag Mhathghamhna and O Hannluain descended from Colla Da Chrioch.
In the time of Cormac son of Art, also, the Deisigh, a tribe of the race of Eireamhon, came to Munster and acquired territory there. And it was while Fiachaidh Muilleathan son of Eoghan Mor, son of Oilill Olum, was king of Munster, that Cairbre Musc, a nobleman of the race of Eireamhon, brought a poem to Fiachaidh, and obtained all the land that lies between Slighe Dhala, that is, Bealach Mor Osruighe and Cnoc Aine Cliach, as a reward for his poem, as we read in the Book of Ard Macha; and it is from this Cairbre Musc that the name Muscruidhe Tire is given to the two Ormonds. And soon after this, some of the race of Eibhear came to Connaught, namely, the descendants of Cormac Gaileang, that is, the Gaileanga and the Luighni, of whom are O Headhra and O Gadhra in the northern half. And so it was with every family and tribe who migrated to another district in Ireland, it was not because of the division made by Eibhear and Eireamhon they migrated; and hence I consider the last-mentioned opinion correct; for it is not likely that it was in the portion which fell to Eibhear in which Airgeadros is situated that Eireamhon would build his first royal fort, that is, Raith Beitheach in Airgeadros. Hence I think that it was in his own portion he built it, and that therefore the province of Leinster belonged to Eireamhon's portion, as the last opinion states.
A learned poet and a melodious harper, the name of the poet being Cir son of Cis, and that of the harper Onaoi, were amongst those who came with the sons of Milidh to Ireland. And Eibhear said that he should have them, while Eireamhon maintained that they should be his. Now the arrangement made between them was to share them with one another by casting lots for them, and the musician fell by lot to Eibhear and the poet to Eireamhon. And as a setting forth of this contest are the following stanzas from the Psalter of Cashel:
They cast lots fairly
For the noble poetic pair,
So that to the man from the south fell
The correct dextrous harper;
To the man from the north fell, too,
The poet of great powers;
And hence came sway
Over honour and learning,
String-harmony of music, beauty, quickness,
In the south and lower part of Ireland:
Thus shall it be for evermore,
As is recorded in the seanchus.
There came to Ireland with the sons of Milidh twenty-four slaves who cleared twenty-four plains from wood after they had come into the country; and it is from themselves these plains are named. Here are the names of these men: Aidhne, Ai, Asal, Meidhe, Morbha, Midhe, Cuibh, Cliu, Ceara, Reir, Slan, Leighe, Lithfe, Line, Lighean, Trea, Dula, Adhar, Airiu, Deise, Deala, Fea, Feimhean, and Seara; and these names are precisely the names of these plains in Ireland at this day.
Moreover, Tea daughter of Lughaidh son of Ioth, the wife of Eireamhon, got a fortress built for herself in Liathdhruim which is now called Teamhair; and it is from Tea daughter of Lughaidh that this hill is called Teamhair, that is, the mur or house of Tea.
The sons of Milidh ruled Ireland jointly for a year, when a dispute arose between them about the possession of the three best hills in Ireland, namely, Druim Clasaigh in the territory of Maine, Druim Beitheach in Maonmhaigh, and Druim Finghin in Connaught. On that occasion a battle was fought between Eibhear and Eireamhon in Ui Failghe at Bru Bhriodain, at a pass between two plains in the district of Geisill. Eibhear was defeated in that battle; and he himself was slain, together with three leaders of his followers, namely, Suirghe, Sobhairce, and Goistean. The poet treats of this event, setting forth the cause of the dispute, as follows:
Banbha without grief shared
Eibhear and Eireamhon,
Till pride seized their wives,
A year without foray, without war.
The wife of Eibhear of the battles said
That unless she owned the fair Druim Clasach,
Druim Beithech, Druim Finghin bright
She would not remain a night in Erin.
Eibhear fell, great the man,
By Eireamhon son of Milidh;
He got his death-wound in the land of Geisill
In the morning on Magh Smearthoin.
The poet Tanuidhe, agreeing with the same statement, speaks thus:
Ye bards of renowned Banbha,
Know ye, or can ye tell,
Why the great battle was fought
Against Eibhear by Eireamhon?
I myself will tell you that
The reason why he committed the fratricide,
Because of three low-lying hills,
The best that were in Erin:
Druim Finghin, fair Druim Clasaigh,
Druim Beitheach in Connaught;
In struggling for these, not bright the tale,
This slaughter was wrought, O bards.