Or perhaps more strictly for the composition of Book I. For Muirchu has divided his work into two Books. The ground of the division is not quite evident. One might have thought that Book I. would naturally have terminated with the episode of Loigaire, where the chronological order ceases. Now at the end of the Table of Contents to Book I. there occurs a notice (of which more will be said below) that Aed helped him; and it might be held that the distinction between Book I. and Book II. was based on the fact that he had Aed’s co-operation in Book I. and not in Book II. In that case Book I. might have been composed before, and Book II. after, Aed’s death.[298] If so, the Preface was written before Book II. In this interesting dedicatory preface, written in a most turgid style, and partly modelled on the opening verses of St. Luke’s Gospel, Muirchu declares, or seems to declare, that he is venturing upon a novel experiment, which had been tried before (in Ireland) only by his father Cogitosus. It is of considerable importance to know on Muirchu’s authority that the Life of Brigit by Cogitosus[299] was a new departure in hagiography in Ireland. As Cogitosus must have written in the seventh century, it follows that before the seventh century hagiographical literature in Ireland must have differed materially in character from the works of Cogitosus and his son. One difference possibly was that the earlier writings, some of which Muirchu used (see below), consisted of _acta_ and _memorabilia_, and were not regular biographies; but there are grounds, as will be shown, for inferring a more important difference, namely, that they were written in Irish. Muirchu aspired to do for Patrick what his father had done for Brigit. But in venturing into what he calls the “deep and perilous sea of sacred story,” he may have been helped by Aed. From the lemma[300] which is found at the end of the Table of Contents to Book I., one might think that Aed has even more claim to be considered the author than Muirchu. _Haec ... Muirchu ... dictante Aiduo ... conscripsit._ Taken by itself, this might almost suggest that Muirchu’s share in the work was little more than that of a scribe. But such an inference is completely contradicted by the dedicatory preface, in which Muirchu takes upon himself the whole responsibility, though he acknowledges that he had undertaken the work in obedience to a wish of Aed.[301] If, then, the lemma has any good authority,—it may be doubted whether it is due to the author himself,[302]—we must interpret it to mean that Aed furnished Muirchu with some of the material. But it is possible that the note has no good authority, and merely expresses the misconception of a copyist.