Cet mac Mágach is a

Connacht Connacht ( ; ga, Connachta or ), is one of the provinces of Ireland, in the west of Ireland. Until the ninth century it consisted of several independent major Gaelic kingdoms (Uí Fiachrach, Uí Briúin, Uí Maine, Conmhaícne, and Delbhn ...

warrior in the

Ulster Cycle The Ulster Cycle ( ga, an Rúraíocht), formerly known as the Red Branch Cycle, is a body of medieval Irish heroic legends and sagas of the Ulaid. It is set far in the past, in what is now eastern Ulster and northern Leinster, particularly coun ...

Irish Mythology Irish mythology is the body of myths native to the island of Ireland. It was originally passed down orally in the prehistoric era, being part of ancient Celtic religion. Many myths were later written down in the early medieval era by C ...

. He had a rivalry with the

Ulster Ulster (; ga, Ulaidh or ''Cúige Uladh'' ; sco, label= Ulster Scots, Ulstèr or ''Ulster'') is one of the four traditional Irish provinces. It is made up of nine counties: six of these constitute Northern Ireland (a part of the United King ...

warrior

Conall Cernach Conall Cernach (modern spelling: Conall Cearnach) is a hero of the Ulaid in the Ulster Cycle of Irish mythology. He had a crooked neck and is said to have always slept with the head of a Connachta, Connachtman under his knee. His epithet is normal ...

. In some myths, he is said to be the brother of Conall's mother, making him Conall's uncle. At a feast at the house of Mac Dá Thó, a hospitaller of

Leinster Leinster ( ; ga, Laighin or ) is one of the provinces of Ireland, situated in the southeast and east of Ireland. The province comprises the ancient Kingdoms of Meath, Leinster and Osraige. Following the 12th-century Norman invasion of Ir ...

, the warriors of Connacht and Ulster competed for the champion's portion by boasting of their deeds. Cet shamed all comers by reminding them how he had bested them in combat. However, just as Cet was about to carve, Conall Cernach arrived. Conall's boasts topped even Cet's. Cet admitted defeat, but claimed that if his brother Anlúan were present, his feats would top even Conall's. Conall responded by tossing him Anlúan's freshly severed head. Cet killed

Conchobar mac Nessa Conchobar mac Nessa (son of Ness) is the king of Ulaid, Ulster in the Ulster Cycle of Irish mythology. He rules from Emain Macha (Navan Fort, near Armagh). He is usually said to be the son of the High King of Ireland, High King Fachtna Fáthach, ...

, king of Ulster. He stole the calcified brain of

Mesgegra In Irish mythology, Mesgegra (Mess-gegra, Mes Gegra, Mes Gedra) was king of Leinster during the events of the Ulster Cycle, and was also the brother of Mac Da Thó aka Mes Róidia in ''The Tale of Mac Da Thó's Pig''. Mesgegra was killed by the Ul ...

, king of Leinster, which Conall Cernach had taken as a trophy of battle, and shot it from his sling, embedding it in Conchobar's head. Conchobar's doctors couldn't remove it without killing him, so they sewed up the wound and told him he would survive as long as he didn't get excited or over-exert himself. Seven reasonably peaceful years later Conchobar was told of the death of Christ. He flew into a rage, the brain burst from his head, and he died. Cet made a raid on Ulster one winter's day, killing twenty-seven men and taking their heads. It had snowed, so Conall Cernach was able to follow his trail. He caught up with him, but was reluctant to face him until his charioteer chided him for cowardice. They met at a ford, and Conall killed Cet in a ferocious combat that left Conall near to death himself.

See also