The Osraighe, a group of a Munster people known as the Érainn, establish a semi-independent state within the territory of Laigin in the present County Kilkenny c100. The ancient sept of the Uí Dheaghaidh (O'Dea) would appear to have given its name to the barony of Ida (then part of the cantred of Iverk or Overk). About the yeare 571 the people of Osraighe were united with their neighbors to the northwest, the Eile, in a defeat at the battle of Tola, a battle which was apparently won by a chief of the Ulaid (northeast Ireland).
'The Airghialla people may be divided into three main groupings. A northern grouped occupied the territory of Derry and north Tyrone. The Cianacht encompassed the O’Connors (O Conchobhair) of Keenaght, and the Luighne. The O’Connors were lords of Keenaght, County Derry. The Luighne or "race of Lugh," included the Dalriada families of O’Hara (O hEaghra) and O’Gara (O Gadhra). The Ciarraighe Locha na nAirne were originally part of a greater kingdom, the tribal kingdom of Ciarraighe, centered at Cruachu (the ancient capital of Connacht). This kingdom was fragmented by the Uí Briuin of the North Gaels during the late eighth century or early ninth century which itself resulted in the ultimate overkingdoms of the Connachta and Uí Neill. The Ciarraighe Luachra were the original tribe of North Kerry, a branch of the Ciarraighe.
A western group dominated the Clogher area of Tyrone, and the Fernmag territory of west Monaghan, and, in later years, much of Fermanagh. Fir Lemna is thought to have been near Clogher (Clochar mac nDaimin) in modern county Tyrone. The Uí Ceinneidigh, gave its name to the barony of Tirkennedy, co. Fermanagh. These people were called the Uí Chremthainn (from whom the MacMahons descend).
Another in Northern Co. Louth, eastern Armagh and Monaghan. Imchad, the son of Colla Fochríth (one of the 3 Collas) is cited as progenitor of the Uí Méith in the early genealogies. The Gailenga Mora left their name in the barony of Morgallion (Machaire Gailenga, "the plain of the Gailenga") in County Meath. According to the native divisions, Thomond, Meath, and Kildare formed part of one of the five kingdoms into which the Eblani of Ireland was partitioned. - There were two groups of this name (Ui Meith) in the ancient Oirghialla, one called Uí -Meith Macha. alias Ui-Meith Tire, who were seated in the present barony of Monaghan, in the County of Monaghan; and the other Uí-Meath-Mara [Omeath], seated in Cualigne, in the north of the County of Louth. The prince of East Meath was O'Nial, hereditary chieftain of Caelman or Clancolman, who is distinguished in the native annals by the name of the southern O'Nial.
The third grouping included the Airthir people of Armagh as well as the Airghialla clans in east and south Monaghan. In the barony of Dartree in west co. Monaghan, it was also referred to as Dartaige Coininnsi. The O'Boylan (Ó Baoighealláin) sept are cited as early kings of Darty (Dairtre) in Orghialla. There was also a Dartraige centered in Breifne. In spite of the large tract of territory which they ruled, the Airghialla did not form a new province....the Airghialla confederation was subject to constant pressure from the Uí Neill who had established themselves in Donegal. It was afterwards known as the district or kingdom of Cenél Eoghain, frequently called Tyr-Oen, whence its present name of Tyrone is derived. The county once comprised the territories of the O'Birnes and O'Tooles in the south, which were separated from it and formed into the present county of Wicklow, so lately as the yeare 1603. The Uí Faelain included the O’Byrnes (O Broin) and their kinsmen the MacKeoghs or Kehoes (Mac Eochaidh) of Leinster. The O’Byrnes descend from Bran, son of Maolmordha, King of Leinster in 1014. In 841 the Dane Vikings set up fortified camps at Annagassan (county Louth) and Dubhlinn (present day Dublin). Maolmordha died fighting on the side of Earl Sigurd of Orkney against Brian Boru, High-King of Ireland, at the battle of Clontarf in 1014). Their first victories were recorded by Cellachan of Cashel, who sacked the Viking capital of Dublin in 950 AD. Although Dublin under Brian Boru remained a Danish outpost for years after the battle, Viking power was forever broken in Ireland. The battle (Danelaw) actually marks the failed attempt by Leinster and Dubhlinn to assert their independence from Munster.
The Diocese of Clonfert was sometimes referred to as the Bishop of Hy-Many. Here, St Laurence O'Toole, was born at Castledermot (Diseart Diarmada), Kildare- the first Irishman to appointed to the See of this town of Danes and Norwegians. The Diocese of Cloyne comprises the northern half of County Cork. The Four Masters mention Innisfallen, Kilarney the foundation of the structure, whose remains are shown above, in 1340, while some say it was established for the Franciscans in the middle of the Fifteenth century near Muckross.
Ancient Irish tradition tells us that Airghialla (or Oriel) was a territory in North Ireland founded by the three Collas about the 4th century of the Christian Era, and inhabited by their descendants in later centuries. It was when Muiredeach Tireach, grandson of Carbri of the Liffey, was High King of Ireland, that Ulster was despoiled and broken by his nephews, the three Collas, who, on the ruins of the old kingdom of Uladh, founded a new kingdom - of Oirgialla (Oriel) which was henceforth for nearly a thousand years to play an important part in the history of North Ireland. By the 5th century of Laigainian colonization, the Southern Uí Naill encroached on the Northern borders of the province decreasing its area. The Ui Chennselaig and Ui Dunlainge tribes were the dominent septs during this period.
The Uí Dunlainge anciently inhabited the Liffey Plain, the territory around the River Liffey, just to the northwest of the Wicklow Mountains and the Úí Cheinnselaig expanded into Wexford down the Slaney valley through a pass between the Balckstairs and the Wicklow Mountains. The original Úí Bairrche are said to be related to the Brigantes tribe of northern Britain, and that they ruled southern Leinster from the earliest centuries A.D. until their power was broken by the Uí Cheinnselaig. At that time they were split into at least two major groups, the Úí Bairrche of northern Carlow (Uí Bairrche Maighe, aka of Maige hAilbe) and those of southern Wexford (Úí Bairrche Tire, of the barony of Bargy) and the Pictish homeland was mainly in the low-lying coastal areas of Eastern Scotland where they sustained themselves through fishing and farming.
After the Roman withdrawal from Britain in 409, the Picts systematically raided the territories of their southern neighbors. The latter, however, soon put an end to these raids, probably with the assistance of the Saxons, one of the Germanic tribes that subsequently subjugated the Britons.
Although the Osraighe of Ossory-Leix is considered to be part of the the Érainn or Desi of Mumhan (Munster) around the 8th century, the Osraighi of the north-western portion of Ossory have ancient ties to Laigen (Leinster) as documented in the very early genealogies. There, Maine Mál was the ancestor of the Uí Máil, which included the septs of the Úí Theig (O'Tighe) and Úí Ceallaig Cuallan. (Cork & Wicklow)