Irish title of an early 11th-century Irish narrative known in En.glish as The Adventure of the Sons of Eochaid Mugmedón, a part of the Cycle of Kings. Texts survive in the Yellow Book of Lecan and the Book of Ballymote; it is not older than the 11th century. In it the most prominent son of Eochaid Mugmedón is Niall; we learn how he meets a female personification of Ireland and goes on to become the legendary king of Ireland, Niall Noígiallach [of the Nine Hostages].
Eochaid Mugmedón, a wondrous and noble king of Ireland, has five sons, four, Brian, Ailill, Fiachra, and Fergus, by Mongfhind, the daughter of Fidach, and one, Niall, by Cairenn, a daughter of Sachell Balb, a British king. Mongfhind is filled with jealousy from the moment of Niall's conception, forcing the pregnant Cairenn to draw the water, hoping the labour would kill the child before birth. When Cairenn delivers a son, she is afraid to bring it into Tara and leaves Niall exposed to the birds. In fear of Mongfhind's anger, not one of the men of Tara will rescue the child until Torna the poet takes Niall to his bosom, fosters him, and foretells that he will become a great king. Upon reaching maturity Niall returns to Tara, where he finds his mother still drawing water for the household. Niall tells her to cease from such demeaning work to wear the royal purple henceforward because he is the son of the king. Mongfhind, predictably, is enraged, but she is taken to the breaking point when it appears that the common will favours Niall to succeed his father instead of her four sons. She demands that Eochaid Mugmedón choose his successor, but he refuses, giving the task instead to the wizard Sithchenn, who devises a unique contest. He sets fire to a forge with the sons inside. Niall emerges first with the anvil and its block, prompting the wizard to exclaim, ‘Niall vanquishes; and he will be a solid anvil forever.’ The other sons make less satisfactory rescues: Brian, a sledgehammer; Fiachra, a pail of beer and the bellows; Ailill, a chest of weapons; and Fergus worst of all, a bundle of withered wood with a stick of yew in it (symbolizing his sterility). Mongfhind finds these results grievously unacceptable, and bids her sons entrap Niall by pretending to quarrel, enticing him to settle the dispute, and then kill him. The sons comply and Niall is about to take the bait when Torna advises him, ‘Let the sons of Mongfhind be peaceful’, a phrase which has survived as an Irish proverb.
Mongfhind says she will not abide by Sithchenn's test, and asks the wizard to make arms for the sons. He agrees, but gives the finest to Niall. Once armed, the five go hunting, wandering far astray. That night when they set about cooking their quarry they realize they need water, and send Fergus to fetch some. He finds instead, next to a well, a horrible hag, black as coal, with hair like the tail of a wild horse, smokey eyes, a crooked nose, green teeth that can cut oak, and green nails; she is covered in pustules and is in every way loathsome. She wants a kiss; otherwise, no water. Fergus refuses, saying he would rather perish of thirst. Fergus returns to tell his brothers, and one by one the others also go for water. Ailill and Brian refuse the kiss and return empty-handed, but Fiachra gives one small kiss, allowing him to see Tara and, later, to found a royal line in another part of Ireland; still, he does not return with water. Niall agrees to kiss the loathly lady, volunteers to lie with her, and then throws himself upon her, giving her a most passionate kiss. At this the hag is transformed into a wondrous beauty, clad all in royal purple, with bronze slippers on her white feet. She reveals herself as Flaithius, the Sovereignty of Erin, and grants Niall the water, kingship, and domination over the country for succeeding generations. When news of this reaches Mongfhind, she wants to know why the eldest son, Brian, has not received sovereignty. Her four sons answer that they acceded to Niall's seniority and kingship. Sithchenn confirms that Niall and his children will henceforward have the domination and kingship of Erin.
See text and translation by Whitley Stokes, Revue Celtique, 24 (1903), 190–207. The motif (D732) of the loathly lady transformed into gorgeous sovereignty is widespread in medieval literature, being best known in Geoffrey Chaucer's ‘Wife of Bath's Tale’ in the Canterbury Tales (1387–99). See Sigmund Eisner, A Tale of Wonder: Source Study of the Wife of Bath's Tale (Wexford, 1957).