Cormac was the son of Art the Solitary, or the Melancholy, as he is sometimes called, and was grandson of the celebrated Conn the Hundred-Fighter. Hence he is sometimes called Cormac O'Cuinn, as well as Cormac Mac Art. His father was slain about the year A.D. 195, in the great battle of Magh Mucruimhe where, as at the battle of Aughrim in the same county, a kingdom was lost and won. Magh Mucruimhe was the ancient name of the great limestone plain extending from Athenry towards Oranmore; and the spot where King Art was killed has been called Tulach Art even down to our own times. It was between Oranmore and Kilcornan, and close to the townland of Moyvaela.[28] The victor in this great battle was Lughaidh, surnamed Mac Con, who had been for many years a refugee in Britain, and now returned with the king of that country and a host of foreigners to wrest the kingdom from Art, who was his maternal uncle. The flower of the chivalry of Munster perished also on that fatal field; for the seven sons of Ollioll Olum who had come to assist King Art, their mother's brother, were slain to a man on the field or in the rout that followed. Fortunately for young Cormac, the king's son, he was just then at fosterage in Connaught, probably with Nia Mor, who was his cousin, and one of the sub-kings of the province at that time. So Mac Con, the usurper, found no obstacle to prevent him assuming the sovereignty of Tara; and we are told that he reigned some 30 years, from A.D. 196 to 226. Meantime young Cormac was carefully trained in all martial exercises, as well as in all the learning befitting a king, until he came to man's estate. Then he came to Tara in disguise, and according to one account, was employed in herding the sheep of a poor widow, who lived close to Tara, when some of the sheep were seized for trespassing on the queen's private green or lawn. When this case of trespass was brought before the king in his court on the western slope of the Hill of Tara, he adjudged that the sheep should be forfeited for the trespass. "No," said Cormac, who was present, "the sheep have only eaten of the fleece of the land, and in justice only their own fleece should be forfeited for that trespass." The bystanders murmured their approval, and even Mac Con himself cried out--"It is the judgment of a king"--for kings were supposed to possess a kind of inspiration in giving their decisions. Then immediately recognising Cormac, whom he knew to be in the country, he tried to seize him on the spot. But Cormac leaped the mound of the _Claenfert_, and not only succeeded in effecting his escape, but also in raising such a body of his own and his father's friends, that he was able to drive the usurper from Tara. Mac Con fled to his own relatives in the South of Ireland, where he was shortly afterwards killed, at a place called Gort-an-Oir, near Cahir, in the Co. Tipperary.