Cryptography and the alphabet in the “Book of Ádhamh Ó Cianáin”

This chapter examines two small items of a grammatical nature in the compilation now catalogued in the National Library of Ireland as MSS G 2 and G 3, which contains some of the earliest extant Irish-language material from the post-Norman period. Much of this compilation was written in the fourteenth century by the Fermanagh scribe Ádhamh Ó Cianáin, seemingly for his own use. The items in question reflect engagement with doctrine on cryptography and the letters of the alphabet as transmitted in some versions of the tract known as the De inventione linguarum (or litterarum), a text which circulated in several Continental Latin manuscripts from as early as the ninth century. The evidence that these entries provide for the relationship between the G 2–G 3 compilation and texts preserved in later Irish manuscripts will be discussed, as well as their significance for our understanding of Ádhamh’s broader compilatory motives.