The Salmon of Knowledge is the ancient Irish legend of the folklore hero Finn Mac Cumhaill came to have all world’s knowledge.

The story of Finn and Salmon of Knowledge begins long before he was born. Finn’s father, great Cumhaill, head of Clan Bascna and leader of Fianna, had fallen in love with Muirne, daughter of a Druid called Tadg who lived on Hill of Allen.

Despite Tadg’s refusal to let Cumhaill take Muirne’s hand in marriage, young couple eloped. When Tadg heard the news, he was so furious that he went to King, Conn, who gathered many chiefs and soldiers from Clan Morna to fight Cumhaill for Muirne’s return.

The two clans met at Cnuca, near Castleknock and although Cumhaill fought bravely his small army was overpowered and he was killed. The leader of Clan Morna was rewarded with the honor of replacing Cumhaill as head of Fianna. When Muirne realized her husband had been killed, she returned to her father’s castle on Hill of Allen, but Tadg was still angry with her and banished her from his home.

Read more: Top ten stories and figures from Irish mythology

Frightened and scared for her safety, Muirne fled to Conn and asked him to take her in, which he did. Not long after, Muirne gave birth to a baby boy – son of Cumhaill – and she called him Demne. Muirne knew Demne wouldn’t be safe from Clan Morna, so she sent the baby to be raised by two of her closest servants, women who knew how to survive in the wilderness. It was with these two women that Demne was raised, deep in the forest in a hidden house of mud and branches.

"Muirne gave birth to a baby boy – son of Cumhaill – and she called him Demne"

"Muirne gave birth to a baby boy – son of Cumhaill – and she called him Demne"

Over years, Demne’s carers taught him to be a great hunter and tracker. As he grew older, Demne’s curiosity brought him out of woods into a clearing where other boys his own age were playing hurling on the field. Demne joined the game and proved to be by far strongest and most skilled player, beating all other boys single-handedly before retreating back into the forest.

When chieftain’s son told his father of the mysterious boy who had played with them, the leader named him Finn, which means ‘fair-haired’. The chieftain’s son was jealous of Finn’s prowess, and next day when he returned to play, he turned all other boys against him and chased him out of the clearing. Finn’s carers knew that his secret identity would be revealed and he would only be safe if he left the forest and traveled south to hide once again from Clan Morna.

Read more: Irish myths and legends - the giant and the baby

Finn traveled until he reached Kerry and sought refuge with King of Bantry, but when King saw handsome young traveler, he recognized him immediately as Cumhaill’s son. The King told him to leave, as he could not protect him, and once more, Finn traveled until he settled with his uncle. Here, he was protected and told stories of his father great warrior, and of Fianna.

Finn soon made the decision to take back his birthright as leader of Fianna by fighting Mac Morna, but he knew first he must become the greatest hunter and wisest poet. Finn went to study with Finnegas, the wisest man in Ireland, who lived by a rock pool on River Boyne. Finnegas had been there, patiently looking for Salmon of Knowledge for seven years. The red-speckled fish lived in these waters and was said to hold all secrets of the world, and he who ate him would absorb all this knowledge.

Finnegas finally caught salmon he had been waiting for.

Finnegas finally caught salmon he had been waiting for.

As Finn sat with Finnegas, the old man finally caught salmon he had been waiting for. Finnegas told Finn to clean and cook fish, but warned young man not to taste it, as Finnegas knew that first one to taste salmon would be one to get its Knowledge. As Finn was cooking fish, he burnt his thumb and immediately raised it to his mouth to ease the pain. When he brought salmon to Finnegas, he immediately saw a difference in his pupil’s face. “Did you eat salmon?,” asked Finnegas. Finn told truth and said that he had not eaten salmon, but had burnt his thumb and put it to his mouth. Finnegas knew that Finn had absorbed eternal Knowledge and that he was to become a great man.

Here's a short guide on how to pronounce some of the ancient Irish names including in these Irish legends.

a short guide on how to pronounce some of the ancient Irish names including in these Irish legends.

a short guide on how to pronounce some of the ancient Irish names including in these Irish legends.

* Illustrated by P.J. Lynch. Originally published in July 2013 on Ireland of the Welcomes.

Finn Mac Cumhaill burned his thumb on the Salmon of Knowledge and put it in his mouth to sooth it. P.J. Lynch