Tenth- and 11th-century Irish narrative, known in English as The Wasting Sickness of Cúchulainn or The Sickbed of Cúchulainn and The Only Jealousy of Emer; it is most often referred to by the truncated title Serglige Con Culainn. The text in the 12th-century Book of the Dun Cow [Lebor na hUidre] combines two versions of earlier composition, causing some incoherence in the surviving narrative; as the full title suggests, what we have may derive from two earlier stories. Cúchulainn's wife is known first as Eithne Ingubai and secondly as Emer.
The men of Ulster are assembled at Mag Muirtheimne during Samain when a flock of beautiful birds settles on a nearby lake. Learning that all the women desire the birds, one for each shoulder, Cúchulainn hunts them and gives two to each noble woman so that none is left for his wife. He promises her two different birds, who are linked with a golden chain and sing a sleep-inducing song. After only grazing them with his spear, Cúchulainn falls into a deep sleep while seated next to a pillar-stone. In a dream he sees two women, one in green, the other in red, laughing and whipping him, at first playfully but then so severely that all the strength drains from his body: thus his wasting sickness. Wakened, he asks to be carried to the Téte Brec [twinkling hoard] of Emain Macha.
Here Cúchulainn lies prostrate for almost a year, until shortly before the next Samain, when an otherworldly man appears next to his bed, offering a cure in a cryptic song. Identifying himself as Angus (1), the son of Áed Abrat, he invites Cúchulainn to come with him to Mag Cruachna (Co. Roscommon), where he will be healed and where Angus's sister Fand is longing to be with him. Cúchulainn is then carried back to the pillar-stone where he was stricken, and there meets a beautiful woman. Dressed in green, she is one of the two who whipped him in his dream. Identifying herself as Lí Ban [paragon of women], she says she means no further harm and instead seeks Cúchulainn's friendship. She brings greetings from her husband, Labraid Luathlám ar Claidib [swift hand on sword] of Mag Mell, who promises him Lí Ban's beautiful sister Fand, now released from her husband Manannán mac Lir, in return for only one day of service in fighting Labraid's enemies, Senach Siaborthe, Eochaid Iúil, and Eochaid Inber. Cúchulainn is intrigued with the offer, especially remembering Fand's renowned beauty, but as he is still on his sickbed he sends his charioteer Láeg to investigate for him. Láeg sails with Lí Ban in a bronze boat to an island where they are greeted by Fand and her company of women, as well as by Labraid, who expresses his disappointment that Cúchulainn has not come. On his return Láeg regales Cúchulainn with descriptions of Mag Mell. After Láeg calls for her, Emer also visits Cúchulainn, urging him to rise from his sickbed; she chides him for being weakened by ‘woman-love’, and calls for him to throw off his wasting sickness. He then arises, and finds that his weariness has passed from him. Shortly after, by the pillar-stone where he had slept, Cúchulainn again encounters Lí Ban, who bids him again to come to Mag Mell. Not wishing to respond to a woman's call, Cúchulainn again sends Láeg on his behalf, who travels over land this time; once there he again finds Labraid, together with a regent, Fáilbe Finn. On his return, Láeg again reports on the wonder of what he has found and tells Cúchulainn he would be a fool for not going forth.