Originally posted May 1, 2014. Updated July 24, 2016.
Legend tells the story of how a boy called Fionn became a wise man by being the first person to eat the Salmon of Knowledge. Fionn would go on to lead a band of warriors known as the Fianna and become one of the greatest heroes in Celtic Mythology – Fionn mac Cumhaill (in English, Finn McCool).
In the River Boyne lived a magical fish called the Salmon of Knowledge. A druid had foretold that anyone who ate the salmon would gain its magical powers and have the knowledge of all things. An old poet, Finnegas, who lived along the Boyne with his student, Fionn, had spent many years trying to catch the salmon. He had hoped to be first to eat it and gain its magical powers.
One day Finnegas came rushing to the door of the hut. “I have caught the Salmon of Knowledge,” he cried happily. Quickly Fionn lit a fire and soon the salmon was cooking. “Look after the fish while I get some more firewood,” ordered Finnegas, “but you are not to taste it,” he warned Fionn.
As Fionn cooked the salmon he burned his finger and instinctively he put his finger in his mouth to ease the pain. Unknowingly he was the first to taste the Salmon of Knowledge. Finnegas came back and Fionn told him what had happened. Finnegas decreed, “You will gain great powers, you must now go and become leader of the Fianna.” And so it was.
The salmon also figures in Welsh versions of the tale of King Arthur and in an echo of older Celtic myths, the hero Culhwch is carried on the back of a magical salmon. The fish, as a symbol of wisdom in Celtic art, persisted with the coming of Christianity. The association of Jesus as a fisherman was one of the many aspects of Christianity that appealed to the Celts.