Phases of Irish History

by Eoin Mac Neill

What and whence was this new ruling power in Munster, the Eoghanachta? Their genealogies show that at one time they were worshippers of a god named Segomo—one of their ancestors is named Nia Segomon, "Segomo's champion." This god Segomo is unknown to Irish tradition, in which his name is never found outside of the Eoghanacht genealogy. He was known, however, and worshipped in Gaul, where he is commemorated in several inscriptions of the Roman period. He was a war-god and is equated, according to the fashion of Roman Gaul, with the Latin god Mars—"Deus Mars Segomo." The descendants of Segomo's Champion are named in three Ogham inscriptions, all found in the district of Dungarvan and Ardmore, on the southern seaboard. The indications therefore are that the Eoghanachta represent a relatively late Gaulish settlement in that part of Ireland. The story of the Déisi Migration mentions several bodies of Gaulish settlers.

The Migration of the Déisi is an evident sequel of the conquest of Tara and eastern Meath under Cormac. Déisi means "vassal communities." These particular vassal communities dwelt around Tara, and were possibly identical with the Luaighni, who formed the chief fighting force of North Leinster in Cú Chulainn's time. They quarrelled with Cormac, we are told, and he drove them, or a large part of them, out of Meath. They migrated in two bodies. One body crossed the sea and settled in southern Wales where the descendants of their princes still held sway in the eighth century. The other body settled for a time in Leinster.

Later on this Leinster section entered into an alliance with the Eoghanacht king, Oengus, whose queen was the daughter of their chief. By their aid, Oengus conquered what is now the south-eastern part of Munster, and he settled the Déisi as frontier colonists on the conquered territory. Oengus flourished in St. Patrick's time, the second and third quarter of the fifth century.

The loss of the large territories about the Boyne and the Suir reduced Leinster to much smaller dimensions. What remained of the two ancient Fifths was now united in one kingdom, ruled over by the line of the ancient kings of South Leinster. This reduction and unification means the final passing away of the Pentarchy described in the Ulster tales. The seat of the Leinster kings is no longer either Tara or Dinn Riogh, but Ailinn, which lies between them, on the southern side of the Curragh of Kildare.

The Connacht kings continued, however, to extend their conquests and their power. A grandson of Muiredach Tirech was king of Tara at the beginning of the fifth century (c. A.D. 400), Niall of the Nine Hostages. His brother, Brión (or Brian) took possession of a south-western section of Ulster, comprising a large part of the counties of Leitrim and Cavan, afterwards called Brian's Land—Tír Briúin. Three sons of Niall took possession of what remained of western Ulster, now comprised in the county of Donegal. Their names were Eoghan, Conall, and 'Enda, and the territories occupied by them were called Eoghan's Land, Conall's Land, and 'Enda's land.

Another son of Niall, named Coirbre, obtained a piece of Leinster, now the barony of Carbury in Co. Kildare.

The Connacht dynasty and its branches now ruled over the northern half of Ireland, with the exception of the eastern seaboard region from Ardee to the Giant's Causeway. It ruled in Tara, and its chief kings were recognised also as Monarchs of Ireland.

The Connacht power, after the time of Niall, was regarded as comprising three chief divisions—the kingdom of Connacht, the Airgialla, and the territory of the descendants of Niall (Uí Néill). All Leinster was laid under tribute to them, and a note in the Book of Leinster says that this Leinster tribute was divided equally among the three sections. This subdivision of the Connacht power, in my opinion, was what gave rise to the ancient term Teora Connachta, "the Three Connachts"—a term which seems to have caused some trouble for its explanation to writers of a later age.

An unpublished tract in the Book of Lecan, also found in the introductory part of the Book of Genealogies by MacFir Bhisigh, tells us that during this period, the succession to the Monarchy was regulated in this way: On the death of the Ardri, the king of Connacht took his place as king of Tara. A new king of the same family was elected in Connacht, and this process went on during several generations. Niall was king of Connacht first, of Tara afterwards. And so, in like manner, the high kingship was filled from Connacht until the death of Ailill Molt in A.D. 483 or thereabouts.

The two facts, then, that explain the transformation of the Pentarchy at the beginning of the Christian Era into the Monarchy and seven principal kingdoms of St. Patrick's time, are these: In the northern half of Ireland, the gradual conquest achieved by the Connacht dynasty; in southern Ireland, the rise of a new power, that of the Eoghanacht kings, centred in Cashel. Along with the direct control of northern Ireland, the Connacht dynasty obtained predominance over the country in general, and this predominance found its natural expression in the high kingship.