The comparison of these two versions, from the literary point of view, is most interesting.  The stress laid on the supernatural cow is peculiar to the version in the later manuscript, the only analogy in the eleventh century version is the semi-supernatural feeding of the army of Ireland, but in this it is a herd (buar), not a single animal, that is credited with the feat, and there is really nothing supernatural about the matter; it is only the other version that enables us to see the true bearing of the incident.  The version in the Glenn Masain Manuscript looks much more ancient in idea than that in the older texts, and is plainly capable of a mythic interpretation.  It is not of course suggested that the Glenn Masain version is ancient as it stands:  there are indeed enough obvious allusions in the text to comparatively late works to negative such a supposition, independently of linguistic evidence, but it does look as if the author of the eleventh century text had a super natural tale to work upon, some of whose incidents are preserved in the Glenn Masain version, and that he succeeded in making out of the traditional account a story that practically contains no supernatural element at all, so that it requires a knowledge of the other version to discover the slight trace of the supernatural that he did keep, viz. the feeding of the army of Ireland by the herd (not the cow) of Flidais.

It is possible that the common origin of the two versions is preserved for us in another place, the Coir Annam, which, though it as it stands is a Middle Irish work, probably keeps ancient tradition better than the more finished romances.  In this we find, following Stokes’ translation, given in Irische Texte, iii.  P. 295, the following entries:—­

“Adammair Flidaise Foltchain, that is Flidais the Queen, one of the tribe of the god-folk (the Tuatha de Danaan), she was wife of Adammair, the son of Fer Cuirp, and from her cometh the name Buar Flidaise, the Cattle of Flidais.

“Nia Segamain, that is seg (deer) are a main (his treasure), for in his time cows and does were milked in the same way every day, so that he had great wealth in these things beyond that of all other kings.  The Flidais spoken of above was the mother of Nia Segamain, Adammair’s son, for two kinds of cattle, cows and does, were milked in the days of Nia Segamain, and by his mother was that fairy power given to him.”

It seems, then, not impossible that the original legend was much as stated in the Coir Annam, viz. that Flidais was a supernatural being, milking wild deer like cows, and that she was taken into the Ulster Cycle and made part of the tale of Fergus.