One of the great codices of late medieval Irish learning produced by the learned family of Mac Fhir Bhisigh in north Connacht, its full title is the Great Book of Mac Fhir Bhisigh of Leacan. It was compiled by Giolla Iosa (son of Donnchadh Mor) Mac Fhir Bhisigh, who was also the principal scribe—almost 260 of the manuscript’s surviving 311 folios are in his hand. (A small number of the book’s original vellum folios—perhaps a dozen or so—have been lost over the centuries.) Giolla Iosa informs us that he was writing the book "for himself and for his son after him," while three colophons pinpoint the time of writing—two refer to "the autumn Mac Donnchaid was killed" and a third to "the winter after Mac Donnchaid['s death]." Scholars have interpreted this information differently. Eugene O’Curry thought it indicated the year 1417, while Paul Walsh suggested that it reflected the death in 1416 of "Mac Donnchaid . . . chief of Tirerrill, in the present county Sligo." But, as Tomas O Concheanainn has pointed out, the only death of a MacDonagh chieftain that suits the context is that of Tomaltach mac Taidhg, king of Corann and Tir Oilealla since 1383, who was slain in a dispute in north Connacht in mid-August (early autumn in the medieval Irish view), 1397. (It was in this Tomaltach’s house in Ballymote that part of the codex known as the Book of Ballymote was written circa 1391; Tomaltach, incidentally, was a second cousin of Giolla Iosa’s wife, Caithirfhiona.) The suggestion that the manuscript was being written by 1397 is corroborated by some of the terminal dates in the valuable corpus of genealogies preserved in the Book of Lecan; these indicate that work was in progress during the period from 1397 to 1403.
Giolla Iosa’s earliest assistant in writing the manuscript was Murchadh O Cuinnlis, apparently a native of east Galway. Evidently a pupil or apprentice of Giolla Iosa’s—he refers to him as his aidi (master or teacher)—he appears to have left the Clann Fhir Bhisigh school at Lackan, County Sligo (whence the name of the book), by 1398, for from 1398 to 1399 he was in present-day County Tipperary, penning "an excellent manuscript" (O Concheanainn’s description) that is now part of the composite volume, the Yellow Book of Lecan. A decade later—as O Concheanainn has shown—he was at work on "the largest Irish vellum manuscript by one scribe," the compendium of medieval Irish ecclesiastical material known as the Leabhar Breac.
In 1418, a later scribal assistant, Adhamh O Cuirnfn, penned some 23 folios of the manuscript for Giolla Iosa. (This same scribe has been recognized in recent times as having also written, circa 1425, a manuscript in the National Library of Scotland—known as the "Broad Book" of John Beaton, from its owner in 1700.) A third scribal assistant is unnamed, but he has been convincingly identified—on the basis of strong circumstantial evidence—as Giolla Iosa’s (only?) son, Tomas Cam. Among the items he penned is the lengthy poem (of some 900 lines)—replete with genealogical and topographical detail—that his father composed as an inauguration ode for the local chieftain Tadhg Riabhach O Dubhda, who succeeded his brother, Domhnall, early in 1417. The poem contains a great deal of genealogical and topographical detail that mirrors that found in the fascinating prose survey of much of Counties Mayo and Sligo, which is preserved in the Book of Lecan, and is very probably also the work of Giolla Iosa. It may be noted that the author himself makes a number of textual interventions—in what seems a somewhat infirm hand—throughout the poem.
Unlike the other great Clann Fhir Bhisigh manuscript, the principal component (which I have dubbed Leabhar Giolla Iosa) of the so-called Yellow Book of Lecan, whose contents are almost wholly literary, most of the contents of the Book of Lecan have a historical or quasi-historical slant. The volume opens (fols. 1-13v, 16v-21v) with two slightly differing copies of the B-version of Lebar Gabala Erenn (The Book of the Taking of Ireland)—alternatively styled "Redaction 2" and Miniugad—and it closes (264-311) with the C-version—or "Redaction 3"—of the same work. The genealogies of the saints of Ireland (34-51) are followed (53-138v) by an important recension of the medieval Irish secular genealogies, with some related miscellaneous materials scattered throughout the volume (176-183, 213v, 215-229v). (Broadly similar versions of both the saints’ and secular genealogies may be found in the other great north Connacht codex, the Book of Ballymote.) Other important texts in the book include Sex Aetates Mundi (22-26), the Lebor Bret-nach (an Irish version of the Historia Brittonum by Nennius; 139-145), Auraicept na nEces ("The Poets’ Primer;" 151-162v), Coir Anmann ("The Fitness of Names;" 173-175), Lebor na Cert ("The Book of Rights;" 194-202v), the Banshenchus ("History and Genealogies of Famous Women;" 203-212), and Version C of the Dinnsenchas ("Lore of Famous Places;" 231-263v). In addition, there are numerous shorter prose texts as well as many poems—about twenty of 20 quatrains and upwards (one running to 305 qq, another to 181). (Except in the genealogical portion of the manuscript, most pages are laid out in double columns of 51 lines each.)
The Book of Lecan seems to have remained in the hands of Clann Fhir Bhisigh until the early 17th century, but by October 1612 had come into the hands of Henry Perse, secretary to the Lord Deputy, Sir Arthur Chichester. It later passed into the possession of the scholarly James Ussher, Protestant archbishop of Armagh, from whose library in Drogheda it was lent in 1636 to Conall Mageoghegan of Lismoyny, County Westmeath, translator of the Annals of Clonmacnoise. Around this time it was also drawn upon as a source by Brother Micheal O Cleirigh, and it may have been in north Tipperary for a period after that. In 1640, Ussher left Ireland for England, never to return, and his library followed some time later. On his death in 1656, his daughter offered his valuable collection of books and manuscripts for sale. The Cromwellian government, wishing to prevent it from going to foreign purchasers, decided that it should return to Ireland, to form the nucleus of the "second college" being planned for Dublin. The latter proved abortive and, following the Restoration, Charles II bestowed the collection on Trinity College. There it was consulted in 1665 by none other than Dubhaltach Mac Fhir Bhisigh, kinsman of the compiler. It remained in TCD until the outbreak of the Williamite War in 1688. By 1702, it was noted as being missing from Trinity College and the following year it turned up in France. Some time subsequent to that it came into the possession of the Irish College in Paris. In 1787, through the intercession of Colonel Charles Vallancey, the rector of the Irish College, Abbe Charles Kearney, presented it to the newly founded Royal Irish Academy, Dublin, where it has remained ever since. (A small portion—nine folios, 142-150—has been part of another manuscript—1319 or H.2.17—in Trinity College, Dublin, since 1688.) In 1937, the Irish Manuscripts’ Commission issued a facsimile edition of the manuscript, with a detailed introduction by Kathleen Mulchrone.
