 It should not be confused with the "Great Book of Lecan".The book contains nearly the whole of the Ulster Cycle, including a partial version of the "Táin Bó Cúailnge" which is a compilation of two or more earlier versions, indicated by the number of duplicated episodes and references to other versions in the text.This incomplete "Táin Bó Cúailnge" overlaps with the partial version given in the Book of the Dun Cow; the complete text known today was derived from the combination of these s. The version of Fergus mac Róich's death tale in the "Yellow Book of Lecan" is the oldest one that survives.