Fionn mac Cumhaill — pronounced 'fin mac-COOL', often anglicised as Finn McCool — is the central hero of the Fenian Cycle, the body of Irish legend that grew up around the warband called the Fianna. In the older stories he is a normal-sized man, the leader of a roving band of hunter-warriors who guarded the coasts of Ireland under the High King. In the later folk tradition — the version most Irish children grow up on — he is a good-natured giant with a temper, a clever wife, and a habit of hurling rocks across the sea.
The most famous of those rock-throwing stories is the one that explains the Giant's Causeway. According to the folk version, Fionn had a long-running feud with a Scottish giant called Benandonner. He could hear Benandonner shouting threats across the North Channel, and finally he lost patience: he tore up the cliffs of Antrim in great six-sided blocks of basalt and laid them in a road across the sea-bed so he could march to Scotland and settle the argument in person.
Halfway across he caught sight of Benandonner properly for the first time, and discovered the Scotsman was twice his size. Fionn turned and ran back to Ireland with the Scottish giant chasing him over the new causeway.
When he got home, his wife Oonagh sized up the situation in a heartbeat. She dressed Fionn in a baby's bonnet and a baby's smock and tucked him into the family cradle. When Benandonner thundered up to the door asking for Fionn, Oonagh fed the Scotsman cakes baked over an iron griddle (so they broke his teeth), pointed to the cradle, and said her husband was out hunting — but did he want to see the baby first?
Benandonner looked at the enormous infant in the cradle. He worked out the implied size of the father. He turned around and ran back to Scotland so fast he tore up the causeway behind him to stop Fionn coming after him. The hexagonal columns at the Giant's Causeway in Antrim, and the matching hexagonal columns on Staffa across the water in the Inner Hebrides, are what is left of his road.
In the older heroic tradition Fionn is also the boy who burnt his thumb on the Salmon of Knowledge and gained the gift of foresight by sucking it. He is the leader who hunted the wide green woods of Ireland with his hound Bran. He is the father of Oisín, who rode west to Tír na nÓg with Niamh of the Golden Hair. The Fianna are still said to be sleeping in a cave somewhere in Ireland, and Fionn will wake when the country needs him most.
Wear something inspired by Fionn mac Cumhaill and you wear the man who laid the basalt road between Antrim and Staffa — the laughing giant in a baby's bonnet, and the boy who became Ireland's greatest hunter for the sake of one burnt thumb.