Irish and Latin variants of the title ‘the Book of Sligo’ are attested in a number of sources from the 15th and 17th centuries. Its identity cannot be established beyond doubt nor is it necessarily true that the references are all to the same manuscript. Pádraig Ó Riain (CGSH, p. lii) has shown that those at least that can be dated to the 17th century refer to the Book of Lecan (Co. Sligo): these are James Ussher’s quotation of a triad about ‘St Patrick’s three Wednesdays’ and a Latin note added (by Ussher?) to a copy of the Vita sancti Declani which credits the Liber Sligunt as the source for a copy of the genealogies of Irish saints. There are two 15th-century mentions by the Irish title Leabhar Sligigh: one by the scribe of Aided Díarmata meic Cerbaill (first recension) in Egerton 1782, who acknowledges the Leabhar Sligig as having been the exemplar of his text; and an honourable co-mention, with Saltair Caisil, in a poem on the king of Tír Conaill, beg. Dimghach do Chonall Clann Dálaigh. Aided Díarmata is not found in the Book of Lecan, at least in the form in which it survives today. Ó Riain allows for the possibility that ‘the Book of Sligo’ “is indeed a lost codex whose name was mistakenly applied in the seventeenth century, perhaps by Ussher, to the well-known Book of Lecan”.
