A burnt thumb made Fionn mac Cumhaill the wisest hero in Ireland
The poet Finnegas spent seven years hunting one salmon in the Boyne, prophesied to grant whoever ate it complete knowledge. He caught it and told his young pupil to cook it. The boy burnt his thumb, sucked it and absorbed the wisdom himself, earning a new name: Fionn.
Fionn mac Cumhaill, sometimes anglicised Finn McCool, heads the Fianna, bands of roving young hunter-warriors, and is also a seer and poet. His name comes from an Old Irish word meaning white, bright or fair, related to Welsh gwyn and Breton gwenn. He was born after his father's death: Cumhall had carried off Muirne when her father refused the match, and was killed at the Battle of Cnucha by Goll mac Morna, who then took over the Fianna. Stories about Fionn make up the Fenian Cycle, much of it told by his son Oisín.
After tasting the salmon, the young Demne, as he was then called, could summon knowledge by putting his thumb in his mouth. Scholars compare the episode to Gwion Bach, the Welsh boy who sipped from a magic cauldron, and to Sigurd sampling the dragon's heart. At ten, Fionn defended Tara from Áillen, a fire-breather who had lulled its men to sleep with music and burned the city every Samhain for 23 years. Armed with a spear that kept him awake, he triumphed and was given command of the Fianna, and Goll stepped aside.
His later tales carry romance and bitterness. He met his wife Sadhbh while hunting, after a druid had turned her into a deer; his hounds Bran and Sceólang recognised her as human. In the story of Diarmuid and Gráinne, Fionn lets healing water trickle through his fingers until the wounded rival dies.
Folklore made him a giant who built the Giant's Causeway so he could cross to Scotland without wetting his feet. When the huge Benandonner came to fight, Fionn's wife Oona disguised him as a baby and fed his rival griddle-cakes baked with irons inside. A popular tradition says he never died but sleeps in a cave with the Fianna, ready to wake in Ireland's hour of need.
Source: Fionn mac Cumhaill
