Lebor na hUidre ‘The Book of the Dun Cow’ is the oldest extant vernacular Irish manuscript. It is the work of at least three scribes. Scribes A and M may have been working towards the end of the eleventh century; the third scribe (or group of scribes), H, was working not long afterwards and revised a number of texts, adding others. Sixty-seven leaves of the manuscript in total have survived; this represents only a portion of the original codex. It contains thirty-two texts including four narratives concerning Mongán: Compert Mongáin ‘The Birth-tale of Mongán’, Scél asa mberar combad hé Find mac Cumaill Mongán ‘A Story from which it is inferred that Mongán was Finn mac Cumaill’, Scél Mongáin ‘A Story of Mongán’, and Tucait Baile Mongáin ‘The Cause of Mongán’s Vision’.