A peculiarity of the LU-YBL version is the number of passages which it has in common with the Dinnsenchas, an eleventh-century compilation of place-legends. The existing collections of Dinnsenchas contain over fifty entries derived from the Tain cycle, some corresponding with, others differing from those in LU.
This version has also embodied a considerable number of glosses in the text. As many of these are common to LU and YBL, they must go back to the common original, which must therefore have been a harmony of previously existing versions, since many of these passages give variants of incidents.
There is no doubt that the version here translated is a very old one. The language in LU is almost uniformly Middle Irish, not more than a century earlier than the date of the MS.; thus it shows the post-thetic he, iat, etc. as object, the adverb with co, the confusion of ar and for, the extension of the b-future, etc. But YBL preserves forms as old as the Glosses:—
(1) The correct use of the infixed relative, e.g. rombith, ’with which he struck.’ (LU, robith, 58a, 45.)
(2) The infixed accusative pronoun, e.g. nachndiusced, ’that he should not wake him.’ (LU, nach diusced, 62a, 30.)
(3) no with a secondary tense, e.g. nolinad, ‘he used to fill.’ (LU, rolinad, 60b, 6.)
(4) Very frequently YBL keeps the right aspirated or non-aspirated consonant, where LU shows a general confusion, etc.
LL has no very archaic forms, though it cultivates a pseudo-archaic style; and it is unlikely that the Leinster version goes back much earlier than 1050. The latter part of the LU Tain shows that a version of the Leinster type was known to the compiler. The style of this part, with its piling-up of epithets, is that of eleventh-century narrative, as exemplified in texts like the Cath Ruis na Rig and the Cogadh Gaidhil; long strings of alliterative epithets, introduced for sound rather than sense, are characteristic of the period. The descriptions of chariots and horses in the Fer Diad episode in YBL are similar, and evidently belong to the same rescension.
The inferences from the facts noted in the foregoing sections may be stated as follows: A version of the Tain goes back to the early eighth, or seventh century, and is preserved under the YBL text; an opinion based on linguistic evidence, but coinciding with the tradition which ascribes the ‘Recovery of the Tain’ to Senchan Torpeist, a bard of the later seventh century. This version continued to be copied down to the eleventh century, gradually changing as the language changed. Meanwhile, varying accounts of parts of the story came into existence, and some time in the eleventh century a new redaction was made, the oldest representative of which is the LL text. Parts of this were embodied in or added to the older version; hence the interpolations in LU.