The Vision which has come down to us under the name of Adamnán is not to be included among his own works. The language and style, which belong to a much later period, are conclusive as to this; while several allusions in it, as that to the donation of Constantine, also point to a later date. Dr. Whitley Stokes, indeed, considers that ‘it is not older than the eleventh century,’ but Professor Windisch, in the preface to his edition, demurs to this conclusion, and holds that it was written in the tenth century, possibly even in the ninth (_Irische Texte_, i. 167 _sqq._). Nevertheless, it is not to be classed among the literary forgeries with which the Middle Ages teem, composed sometimes _animo fraudandi_, sometimes, in the loose views then prevailing as to literary property and literary fame, in order to secure the prestige of a great name. The present work, however, never professes to be Adamnán’s own composition. It invariably speaks of him in the third person, terming him the ‘High Scholar of the Western World,’ and refers to his legislation at the Mórdáil, where he is said to have first received his Vision, and to his subsequent preaching as matters of past history. It remains, then, to be considered how this Vision came to be associated with his name. We have seen that he had become the hero of a saga-cycle, into which fiction had made an entrance: whether we must class the doubtful episodes as historical romance merely, or as facts set off by the aid of fiction. This, however, brings us little further, for it is certain that this popular reputation was earned by his actual achievements: again, therefore, we are faced with the question how to distinguish fact from fiction. It may be that the true author sought for his own teaching the authority of so famous a saint; or he may have had before him an anonymous work, and inserted the name of Adamnán from a like motive, or from a belief in the fact; or, again, the work may be what it professes to be, and may have for its basis a more or less accurate tradition of Adamnán’s own teaching. A tradition, I venture to think, should be allowed a certain weight where it is in conflict neither with ascertained fact nor with probability; and here the probabilities appear to be rather favourable than otherwise, which, perhaps, in the absence of further evidence, is the nearest approach to a conclusion we can hope to make. It is not a forgery; it is not a polemical work, where the author might wish to shoot forth his darts from under the shield of some Ajax of controversy. Neither is it a mere floating legend, ready to be tacked on to any name indifferently; on the contrary, it is written with great care, and with a literary and constructive skill rare at that day. It makes no profession, and betrays no purpose, save to give the substance of the Vision which Adamnán related to the Mórdáil, and of his subsequent preaching. The fashion of the day renders it highly probable