To the _Tain_ is prefixed the following critical exposition, giving a brief account of it in the technical terms of the Scots literature of the remote age in which it was written. “Ceathardha connagur in cach ealathuin is cuincda don tsairsisi na Tana. Loc di cedumus lighe Fercusa mhic Roich ait in rou hathnachd four mach Nai. Tempus umorro Diarmuta mhic Ceruailt in rigno Ibeirnia. Pearsa umorro Fergusa mhic Roich air is e rou tirchan do na hecsib ar chenu. A tucaid scriuint dia ndeachai Seanchan Toirpda cona III. ri ecces ... do saighe Cuaire rig Condacht.” That is--the four things which are requisite to be known in every regular composition are to be noticed in this work of the Tain. The _place_ of its origin is the stone of Fergus, son of Roich, where he was buried on the plain of Nai. The _time_ of it, besides, is that in which Diarmad, son of Cervail, reigned over Ireland. The _author_, too, is Fergus, son of Roich; for he it was that prompted it forthwith to the bards. The _cause_ of writing it was a visit which Shenachan Torbda, with three chief bards, made to Guaire, king of Connaught.[107] O’Flaherty thus concisely and accurately describes the subject and character of the _Tain_:--“Fergusius Rogius solo pariter ac solio Ultoniæ exterminatus, in Connactiam ad Ollilum et Maudam ibidem regnantes profugit; quibus patrocinantibus, memorabile exarsit bellum septannale inter Connacticos et Ultonios multis poeticis figmentis, ut ea ferebat ætas, adornatum. Hujus belli circiter medium, octennio ante caput æræ Christianæ Mauda regina Connactiæ, Fergusio Rogio ductore, immensam bonum prœdam conspicuis agentium et insectantium virtutibus memorabilem, e Cualgnio in agro Louthiano re portavit.”[108] From the expression, “Ut ea ferebat ætas,” Dr Smith thinks that O’Flaherty considered the tale of the Tain as a composition of the age to which it relates; and that of course he must not have seen the Critical Exposition prefixed to the copy here described. From the silence of the Irish antiquaries respecting this Exposition, it is supposed that it must have been either unknown to, or overlooked by them, and consequently that it was written in Scotland.