Probably the least studied of the group of texts ultimately indebted to Chrétien de Troyes' Perceval is an Irish prose tale, Eachtra an Amadáin Mhóir (The Story of the Great Fool). The Arthurian content of its opening section has undoubted links to the work of Chrétien, and in this article I hope to demonstrate that the overall relationship of the two stories is closer than may previously have been appreciated; also that the perceptive and witty response of the Irish work to its celebrated predecessor well repays careful attention.

Eachtra an Amadáin Mhóir survives in four dated and closely related manuscripts, all of them in Dublin:

Trinity College, Dublin 1297 (formerly H.2.6), fols. 223r–241v (1716)

National Library of Ireland G137, pp. 125–64 (1730)

National Library of Ireland G145, pp. 108–76 (1766) (a copy of Trinity College 1297)

Royal Irish Academy 24 P 16, pp. 49–97 (a nineteenth-century transcript of National Library of Ireland G137)

There are also oral versions from Scotland and Ireland, fragmentary notes from Scotland among the papers of J. F. Campbell, plus a literary adaptation – what Alan Bruford has called ‘a sort of attempt at a Gaelic novel’ – with an expanded, three-volume English version. These, and Campbell's papers, are in the National Library of Scotland. There is a great deal of comparative work to be done, but this article will concentrate on the Irish prose tale and its Arthurian pedigree.