Cormac Mac Airt (son of Art), aka Cormac Ua Cuinn (grandson of Conn) or Cormac Ulfada (long beard), is probably the most famous of the ancient High Kings of Ireland, and may have been an authentic historical figure, although many legends have attached themselves to him. He was the son of King Art, son of Conn of the Hundred Battles. He is said to have ruled from Tara, the seat of the High Kings of Ireland, for forty years in the early to mid 3rd century and under his rule Tara flourished. He was famous for his wise, true, and generous judgments. In the Annals of Clonmacnoise, translated in 1627, he is described as....
“ "absolutely the best king that ever reigned in Ireland before himself...wise learned, valiant and mild, not given causelessly to be bloody as many of his ancestors were, he reigned majestically and magnificently". ”
Cormac was conceived when his father, Art, slept with his mistress, Achtan, the night before he fell in the Battle of Maigh Mucruimhe. He played a role in the overthrow of Art's killer, Lugaid mac Con, and his successor Fergus Dubdétach.
Cormac's career is recorded in some detail in the Irish annals. He fought many battles, subduing Ulster and Connacht and leading a lengthy campaign against Munster. He led the first recorded raids on Roman Britain and is credited with gaining territory there, but several times was temporarily dethroned while away from Ireland. He lost an eye in a battle against the Deisi of Meath, whom he expelled into Munster in response.
Many stories have Fionn mac Cumhail living in his time, and the fianna as Cormac's standing army. According to the tale The Pursuit of Diarmuid and Gráinne, Fionn was to marry Cormac's daughter Gráinne, but she ran off with Diarmuid Ua Duibhne.
Although he is usually remembered as a wise and just ruler, one story presents him in a less flattering light. Having distributed all the cattle he had received as tribute from the provinces, Cormac found himself without any cattle to provision his own household after a plague struck his herds. A steward persuaded him to treat Munster as two provinces, the southern of which had never paid tax. He sent messengers to demand payment, but Fiacha Muilleathan, the king of southern Munster, refused, and Cormac prepared for war. His own druids, who had never advised him badly, foresaw disaster, but he ignored them, preferring to listen to five druids from the sidhe supplied by his fairy lover, Báirinn.
Cormac marched to Munster and made camp on the hill of Druim Dámhgaire (Knocklong, County Limerick). His new druids' magic made the camp impregnable and his warriors unbeatable, dried up all sources of water used by the Munstermen, and nearly drove Fiacha to submission. But Fiacha in desperation turned to the powerful Munster druid Mug Ruith for aid, and his magic was too strong even for Cormac's fairy druids. He restored the water and conjured up magical hounds who destroyed the fairy druids. His breath created storms and turned men to stone. Cormac was driven out of Munster and compelled to seek terms.
Cormac owned the wonderful gold cup given to him by the sea-god Manannan mac Lir in the Land of the Living. If three lies were spoken over it, it would break in three; three truths made it whole again. Cormac used this cup during his kingship to distinguish falsehood from truth. When Cormac died, the cup vanished, just as Manannan had predicted it would.
After ruling for forty years Cormac choked to death on a salmon bone. Some versions blame this on a curse laid by a druid because Cormac had converted to Christianity.
(Wikipedia)