The Táin Bó Cúailnge appears alien, primitive, and unimaginably ancient. There are unmistakable signs that this atmosphere is a sophisticated construction of the past, making its historicity a scholarly donné (a thing in a literary work that is taken for granted or expected by virtue of the genre or milieu in which it is contained) well into the twentieth century. As B. K. Lambkin notes, the clarity of perception of its earliest critic, the scribe of the twelfth century Book of Leinster who said, "But I who have written this story, or rather this fable, give no credence to the various incidents related in it. For some things in it are deceptions of demons, others poetic figments; some are probable, others improbable" was forgotten in a desire to have a reliable historical source. It was its apparent 'primitiveness' that caught...