The place-name _Lusca_, 'Lusk,' is originally an _n-_stem making its genitive _Luscan_. This is the regular form in the Annals of Ulster till the year 880, from which date onward it is always _Lusca_ (A.D. 916, 928, &c.). In our text (§ 46) all the manuscripts read _Lusca_.
In slender _io-_stems the dative singular in Old-Irish ends in _-iu_. I find this form in the Annals of Ulster for the last time in A.D. 816 (_Gertidiu_). Thence onward it is always _-i_, as in our text (_hi Cúailgni_ 43, _d'uisci_ 64).
The nasal stem _léimm_ makes its nom. plur. _léimmen_ in Old-Irish. In § 32 we find instead (_tair-_)_leme_. So also _foimrimm_ makes its nom. plural _foimrimme_ in § 163.
The word _dorus_ is neuter in Old-Irish, making its nom. acc. plural either _dorus_ or _doirsea_. In our text (§§ 173, 174) the word is masculine, and makes its nom. plural _doruis_.
_Druimm_ is an _i-_stem in Old-Irish, but in the later language passes into an _n-_stem. In § 51 we find the nom. pl. _drommanna_.
The neuter _grád_ in § 166 makes its nom. plur. _grúda_ for O. Ir. _grád_.[11]
[11] The infinitive _bith_ for O. Ir. _buith_ (91), the dative _cinn_ for O. Ir. _ciunn_ (98, 135), the nom. pl. _sligthi_ for O. Ir. _sligid_ (which I have restored in § 49), the confusion between _do_ and _di_ (e.g. 83), and other details are probably due to the Middle-and Modern-Irish transcribers.
On linguistic grounds, then, I should say that our collection was made some time during the second half of the ninth century. That it cannot be dated earlier is also apparent from another consideration. Professor Zimmer has taught us to search in every ancient Irish text for indications of its having been composed either before or after the Viking period. I find no words from the Norse language in the Triads, or, if there are any, they have escaped me; but there are two distinct references to the Viking age. In § 232, a Viking in his hauberk (_Gall ina lúirig_) is mentioned as one of three that are hardest to talk to; and, in § 44, Bangor in Co. Down is called unlucky or unfortunate, no doubt, as the gloss says, because of the repeated plunderings and destruction of its monastery by the Norse during the early part of the ninth century (A.D. 823, 824).
