The Salmon of Knowledge (An Bradán Feasa)

A magical salmon that possessed all the knowledge of the world.

The Salmon of Knowledge was a legendary fish that lived in the River Boyne. It was said that the first person to taste its flesh would gain all the knowledge in the world.

The poet Finn Eces (Finegas) spent seven years fishing for the salmon. Finally, he caught it and gave it to his young apprentice, Fionn mac Cumhaill (then called Demne), to cook. He warned the boy not to eat any of it.

While cooking the fish, a blister formed on its skin. Fionn pressed it down with his thumb and burned it. Instinctively, he put his thumb in his mouth to cool it. In that instant, he tasted the salmon's oil and absorbed all the wisdom intended for the poet. When Finn Eces saw the light of wisdom in the boy's eyes, he gave him the rest of the salmon to eat.