Clothru was, according to medieval Irish legend, the daughter of Eochu Feidlech, a High King of Ireland. When her triplet brothers, the findemna, were fighting with their father Eochu Feidlech for the high kingship, she was concerned that her brothers might die without heirs. She is said to have seduced the three of them, and conceived Lugaid Riab nDerg. The next day, according to legend, her brothers were indeed killed, and when Lugaid was born, he was their heir. His epithet Riab nDerg ("the red-striped") came from two red stripes around his neck and waist, dividing him into three: above the neck he resembled Nár; from the neck to the waist he resembled Bres; and from the waist down he resembled Lothar. Lugaid later also became a High King of Ireland, so that her incest preserved the line of succession. Incest features further in Clothru's story: she is said to have then slept with Lugaid herself, conceiving Crimthann Nia Náir, who later also became a High King of Ireland. She was thus both Crimthann's mother and his grandmother.
- Joseph O'Neill (ed. & trans), "Cath Boinde", Ériu 2, 1905, pp. 173–185; Edward Gwynn (ed. & trans.), The Metrical Dindshenchas, Dublin Institute for Advanced Studies, 1906, Vol 4, Druimm Criaich Poem 13: Druimm Criach, pp. 43–57; Vernam Hull, (ed. & trans.), "Aided Meidbe: The Violent Death of Medb", Speculum v.13 issue 1, Jan 1938, pp. 52–61
- Whitley Stokes (ed. & trans.), "Cóir Anmann", Irische Texte series 3 vol. 2, 1897, p. 22
- R. A. Stewart Macalister (ed. & trans.), Lebor Gabála Érenn: The Book of the Taking of Ireland Part V, Irish Texts Society, 1956, p. 301-303