Discovered in 1814 in a blocked-off room in Lismore Castle, together with a medieval pastoral staff. Medieval Irish manuscripts are extremely rare, in public or private possession.
Lismore Castle had come into the possession of the Cavendish family through the marriage in 1748 of William Cavendish (1720–1764), later 4th Duke, to Lady Charlotte Boyle, heiress of the Cork and Burlington estates.
A full digital copy of the Book of Lismore has been made available online in partnership with the Library at University College Cork, and the Irish Script on Screen (ISOS) project at the Dublin Institute for Advanced Studies. The digital images can be seen at www.isos.dias.ie