The metrical martyrology, now for the first time printed, was composed in the latter part of the twelfth century by an Irish abbot, and is contained in a single manuscript transcribed in or about the year 1630 by one of the Four Masters, Michael o'clery, to whose industrious and accurate pen we owe the preservation of much of the ecclesiastical and historical litera ture of Celtic Ireland. I propose in this preface, first, to describe the manuscript in which the martyrology is contained; secondly, to notice the author of the poem, and the place in which it was composed thirdly, to consider some of the characteristics Of its language fourthly, to explain the metre in which it is written; fifthly, to give some account of its contents sixthly, to notice the glosses on the text; and lastly, to say a word or two on the present edition.