succeeded by Cathaeir Mor, a distant relative. Conn, who seems to have held the command of the fianna, or military force, during his father's reign, continued to occupy the same position under Cathaeir, having as second in command a brave warrior named Cumhal. This officer, having incurred the displeasure of Conn, fled to Scotland, where he remained in exile for some years. After a brief reign of three years Cathaeir was killed in the battle of Magh Agha (near Tailtin, co. Meath) by Conn, who then succeeded to the throne, A.D. 123. One of his earliest acts was to bestow the kingdom of Leinster on his tutor, Crimthann Culbuidhe, or ‘of the yellow hair,’ a member of the race to which he belonged himself. Cumhal returned from Scotland, and laid claim to the kingdom of Leinster, asserting that he had as much right to it as Crimthann. To vindicate his authority as sovereign Conn summoned to his aid Conall, king of Connaught, and Aedh Mac Morna, captain of the fianna of Connaught. On the other hand, Cumhal formed an alliance with Mogh Neid, king of Munster, Mac Niadh, son of Lughaidh, his nephew, and Conaire II, both then princes and tanists of that province. The Munster chieftains, accompanied by Eogan Mor, son and heir of Mogh Neid, having marched to his aid, Cumhal gave battle to Conn at Cnucha (Castleknock, near Dublin), where the Leinster men and their allies were defeated by Conn, and Cumhal was killed; he was father to the famous warrior Finn Mac Cumhail (Finn Mac Coole).
The union of the Munster forces was only temporary, and on their return after the battle of Cnucha dissensions broke out among them. There were at the time three races in the province. The line descended, as supposed, from Eber, son of Miledh or Milesius, and represented by Mogh Neid, the ruling king; the race of Ith, who had settled in south Munster along with and under Eber, and who were represented by Mac Niadh, son of Lughaidh; and the Ultonian race descended from Ir, and represented by Conaire, son of Mogh Lamha. A colony of the latter, who were called Euronn or Ernaidhe, from an ancestor, Ailill Euronn, driven from Uladh by the Clanna Rudhraidhe, according to the Saltair of Cashel, settled in middle Munster in the time of Duach Dalta Deaghaidh, about the end of the second century B.C. These Ernaidhe, forming an alliance with the race of Ith, in course of time drove the old Eberean tribes back to the western coasts and islands of Munster. This compact was broken up by Dergthine, grandfather of Mogh Neid, and when his son Eogan Mor (better known by his appellation of Mogh Nuadat) succeeded, the power of the Ebereans had so increased that he determined to assert his right to the sovereignty of Munster. Finding himself unequal to the task without allies, he applied to Daire Barrach, king of Leinster, his foster father, who supplied him with troops, upon which he attacked and defeated Aengus, one of his adversaries, at Ui Liathain (Castlelyons, co. Cork). Aengus then sought the assistance of Conn, who sent him five battalions of chosen troops, with which he renewed the contest, but was again worsted at the battle of Ard-neimhedh (the Great Island, co. Cork). Conn then appears to have entered into direct conflict with Mogh Nuadat, but after many defeats was obliged to submit to a division of Ireland between himself and his adversary. The boundary line agreed on was the Eiscir Riada, a gravel ridge running from Dublin to Clarin Bridge in the county of Galway. Thenceforth the north of Ireland was known as Leth Cuinn, ‘Conn's half,’ and the south as Leth Mogha, ‘Mogh's half,’ from which is said to have been derived the name of Munster. The early and continuous use of these names in Irish literature attests the historical reality of the event. The year after the partition of the kingdom war was again renewed between them, owing, according to the ‘Annals of Clonmacnois,’ to the ambition of Mogh Nuadat, who demanded a division of ‘the customs of the shipping of Dublin,’ which Conn having refused, each side prepared for battle; but this story evidently belongs to a later age. The war was carried on during fourteen years, when it was finally brought to a close by the battle of Magh Lena (Moylena in the parish of Kilbride, King's County), in which Mogh Nuadat was killed. He had been married to a daughter of the king of Castile, and on this occasion is said to have been assisted by a body of Spanish troops led by the king's son, who was also killed. He and Mogh Nuadat were buried ‘in two little hillocks, now to be seen at the said plain, which, as some say, are the tombs of the said Owen and Fregus’ (An. Clonmacnois).
Conn now became once more king of all Ireland, and after a reign of thirty-five years was slain by Tiobraide Tireach, king of Uladh, at Tuath Amrois, near Tara, A.D. 157, as he was preparing to celebrate the feis or festival of Tara. He was buried at Brugh na Boinne, the cemetery of the pagan kings of Ireland and his monument, a stone cairn, is mentioned among the tombs enumerated in the ‘Dinnsenchus.’
An ancient treatise attributed to him, and quoted so early as in the ‘Tripartite Life of St. Patrick,’ is in existence, entitled ‘Bailé Chuinn-Ched-Chathaigh,’ ‘The Ecstasy (or Prophecy) of Conn of the Hundred Battles,’ and another entitled ‘Bailé
