"[2] The majority consensus of scholars is that the original manuscript was compiled at Bangor Abbey, County Down, the mother house of Druim Snechta monastery.
Geoffrey Keating was aware of the book, although he does not seem to have had access to it himself in compiling his Foras Feasa ar Éirinn,[4] and believed it dated to before the arrival of Saint Patrick.
[5] The 19th-century scholar Eugene O'Curry found a marginal note in the Book of Leinster, partly illegible, which said that the Cín was compiled by a son of Dauí, king of Connacht.
O'Curry favoured Ernín, son of Dauí Galach, a nephew of Niall of the Nine Hostages and a contemporary of Patrick, but allowed that it may have been a son of Dauí Tenga Uma, a king of Connacht who died at the end of the fifth century[6] (Francis J. Byrne believes the two kings were in fact the same person).
[7] Rudolf Thurneysen, who made a convincing reconstruction of its contents in 1912-13, proposed a date in the early 8th century for the writing of the book.