While the Martyrology of Óengus (al. Félire) was written in the early ninth century, we do not have a copy of the text as early as that. The text was presumably copied time and time again as older copies deteriorated and the copies we have now are only those that survived. The earliest of those date to the first half of the fifteenth century. Not all manuscripts contain the whole of the Félire, however. Some are damaged and are missing leaves; others, like Rawl. B. 512 leave out the calendar itself, but copy the Preface, part of the Prologue, the Epilogue and a lot of the commentary that built up around the text over time. On this page I give you some basic information about the most important manuscript witnesses we now have.
This manuscript, currently bound in two volumes, was written entirely in one hand. Tomás Ó Concheannain has identified the scribe as Murchadh Riabach Ó Cuindlis, who also wrote part of the Book of Lecan. The book appears to have been written in various locations in Múscraige Tíre (Ormond Lower), in north Co. Tipperary, including Cluain Lethan and Lothra (Lorrha) and Uí Forgo (near Ardcroney), where the Félire appears to have been copied ca. 1408. In the 16th century the manuscript was in the hands of the Mac Aodhagains, a notable family of legal scholars, and for most of the 17th century it was in the possession of the convent of Cenél Féichín. Part of it was copied by brother Mícheál Ó Cléirigh while it was there 1629. It then passed through various owners until vol. I was purchased for the Royal Irish Academy in 1789, followed by vol. II in 1844.
The Félire and its accompanying material are found on pp. 75a-106b of vol. I. A special feature of this copy is that the scribe, when copying, adapted the layout to provide ample spacing for glosses and commentary by placing the main text in the top left of the page so as to create extra wide margins. He also added the domincal letters (for tracking Sundays) and the date (in Roman ‘ides’ and ‘nones’) in the margins.
 ‘The scribe’, Ériu 24 (1973) 64-9.
Most of this beautifully decorated manuscript was compiled in 1453 from a now-lost manuscript known as the Psalter of Cashel and other old manuscripts by Seaan Buidhe O’Cleirigh and Giolla na Naemh Mac Aodhagáin for Edmund Butler (d. 1464). In compiling it, they included parts of ‘The Book of the White Earl’, which had been made for Edmund’s uncle, James Butler, 4th earl of Ormond (d. 1452). This book may have been written anytime between 1410 and 1452, and quite possibly towards the earlier end of that period. That the scribes regularly accompanied their patron on the road is evident from the marginal annotations, which place the manuscript in Pottlerath, Kilkenny, Kilfearow and other places at various times. It is a high-quality copy with colourfully decorated initials, which must have had great value even in its day. It was used to ransom Edmund Butler in 1462, when he was taken prisoner by Thomas Fitzgerald, the eighth earl of Desmond. Félire Óengusso is part of the first section of ‘The Book of the White Earl’ in this manuscript.
RIA MS 23 P 3 is a vellum manuscript also referred to as the ‘Félire Beag’. This too is a composite manuscript, consisting of three booklets which were originally independent of one another. The Félire covers folios 1-12 of the first booklet, which contains 19 folios in all. The current foliation and binding ignore gaps and misplacement of leaves. Some earlier foliation indicates that f. 4 was formerly (not necessarily originally) f. 17. It is also clear that what is now f. 12 should precede f. 1. The worn condition of f. 12 indicates that it was the outer folio for a significant length of time, and that which preceded it must therefore have been lost early on. As a result of these gaps, the prologue and the quatrains for May, September and December are now missing. We are fortunate, however, to know the name of the scribe of this booklet: Uilliam Mac an Leagha wrote the manuscript in 1467 in the house of Oedh Ócc Magraith [Aodh Mág Raith] (d. 1491 AU) in a border district between Tipperary and Kilkenny.
Franciscan manuscript A7 (formerly in Killiney) is a fascinating manuscript of 49 folios which are entirely taken up with the Félire. The colophon (f. 48) at the end of the text identifies the scribe as Ruaidhri Ó Luinín, writing on behalf of Cathal Mac Magnusa Meg Uidhir (d. 1498). This manuscript was among a number of manuscripts transported abroad to the Irish College in Rome and onwards to Leuven by the Irish Franciscans. It was used by Mícháel Ó Cléirigh for the Martyrology of Donegal (1630) and by John Colgan for his Acta Sanctorum (1645). The manuscript opens with the Preface, the first page of which is defaced and largely illegible due to wear. Its layout reflects the scribe or patron’s functional and scholarly interest in the text: each quatrain is marked with a capital and spaced out across three lines in large semi-uncial, with a substantial amount of commentary added, and space left open for further additions. The patron, Cathal Meg Uidir, is likely to have had an interest in actively using this manuscript as religious calendar: the scribe as well as later users have added the names of additional saints from e.g. the Martyrology of Gorman and a small bookmark is still found between its pages.
The youngest manuscript in this collection is a paper manuscript containing martyrologies, monastic rules and other religious material, including the Martyrology of Tallaght, the Martyrology of Gorman and the Rule of Ailbe. It is one of the manuscripts compiled by the ‘Four Masters’ – a group of scholars collecting Irish religious material as part of a preservation project run by the Irish College in Leuven and largely directed by Hugh Ward. According to Pádraig Breatnach, who has studied the scribal hands of the Four Masters in great detail, the copy of the Félire in this manuscript was written Mícháel Ó Cléirigh, who compiled it between (roughly) 1627 and 1633. A colophon on f. 93r, between a large body of commentary and the Félire itself, dates the transcription of the preceding part to February 9, 1630, and mentions that the verses belonging to the body of Félire (that is, the commentary) were transcribed from a book written by Siodrach ua Maelconaire in 1534.