A medieval scholar has uncovered an Irish account of the murder of Abel by Cain that explains how the descendants of Cain were turned into mermaids and leprechauns. This short account was found in a fifteenth-century Irish legal text, but the story itself seems to date from between the 10th and 12th centuries.
The text and a translation were published in a paper by Simon Rodway, “Mermaids, leprechauns and Fomorians: a middle Irish account of the descendants of Cain,” which can be found in the 2010 issue of Cambrian Medieval Celtic Studies. Dr. Rodway, who teaches at Aberystwyth University in Wales, researches medieval Welsh and Irish texts.
In the text he found, a short passage relates the killing of Abel, and how God punishes Cain: God created five lumps on Cain after the killing of Abel, i.e. a lump on his forehead, and a lump on each of two cheeks, and a lump on each of his two hands; this was put as a sign for the offspring of Adam and as an example to them on account of the murder that Cain had done…Ambia daugter of Cain, she had the shape of a woman and the tail of a fish; so she could travel the sea and the land; and she was once sleeping under the sea and a trout squirted its spawn into her mouth so that there was fruit of that, and she gave birth to twenty-two children, ie. two of them were of very great size and twenty small children of the girl, ie Formoir was the man and Ispela the girl. It was sung concerning that:
Bec son of a trout, fair his foot
The smallest boy there was.
Becnait, she was the splendid queen
From whom is the line of the leprechauns
The name Fomoir is probably associated with the Fomorians, a race of giants that were said to have inhabited Ireland in ancient times. This text is one of several from the Middle Ages to associate this Irish myth to the biblical story of Cain. In fact, several medieval texts, both from Ireland and other parts of Europe, remarked that various monsters were the descendants of Cain.
The origins of leprechauns date back to Irish folk traditions, with medieval texts describing a mischievous fairy creature who could grant wishes.
Simon Rodway’s article can be found in Cambrian Medieval Celtic Studies, Volume 59, which is published by the Celtic Studies Association of North America.