Captain of the Fianna
Fionn mac Cumhaill is the central figure of the Fenian Cycle and captain of the Fianna, a free war-band that hunted the wilds of Ireland in service to the High King. Born Demne after his father Cumhall fell in battle, he was reared in secret on Slieve Bloom by the druidess Bodhmall and the warrior woman Liath Luachra, and his fair hair earned him the name Fionn, 'the bright one'. The Boyhood Deeds of Fionn tells the turning point: the poet Finnegas, after seven years' angling on the Boyne, at last caught the Salmon of Knowledge, which had eaten the nuts of the nine hazels of wisdom, and set the boy to roast it. Hot fat scalded Fionn's thumb, he put it to his mouth, and the salmon's whole wisdom passed to him. Ever after he had only to bite his thumb to know the truth of a matter.
He won his captaincy at Tara, where each Samhain the fire-breathing Aillen lulled the court with music and burned the hall. Fionn kept himself awake by pressing a poisoned spearhead to his forehead, and took Aillen's head. The cycle around him holds tragedy as well: in The Pursuit of Diarmuid and Grainne the ageing Fionn hunts his young betrothed and the warrior she eloped with across Ireland, and at the end withholds the healing water while Diarmuid dies. The frame-tale Acallam na Senorach, composed near 1200, has the last of the Fianna, Cailte and Fionn's son Oisin, survive centuries to walk Ireland with St Patrick, telling the old deeds place by place.
Later folklore made Fionn a giant. The forty thousand basalt columns of the Antrim coast are explained as his causeway toward Scotland, built to fight the giant Benandonner: the Giant's Causeway. Another strand insists he never died, but sleeps in a cave with the Fianna until Ireland's need sounds the horn.
