Cover story: Mac Giolla Phádraig Osraí 1384-1534 AD, Part I
by Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2020, 1, 1-17 (View this article)
The first part of this review of Mac Giolla Phádraig Osraí history (1384-1534) covers the period 1384, from the conquest of Richard II, to 1455, by which time the clan had entered into an alliance with their mortal enemies, the Butlers of Ormond. Twelve years after the commencement of this era the Lordship of Ossory had fallen to Finghin Óg; these were days of increasing formation of alliances between Gaelic chieftains. That changed around the time of Finghin Óg’s death in ca. 1417; the power struggle between Sir John Talbot and Sir James Butler, 4th Earl of Ormond, altered the face of Irish politics for the next 30 or so years, and Mac Giolla Phádraig Osraí had to choose one side or the other. It was a time when Donnchadh Mór Riabhach, a previously unrecognised Lord of Ossory, was chieftain. His life and times are recounted from entries in the Annals of the Four Masters and other familiar texts, but three largely overlooked sources of Mac Giolla Phádraig Osraí history – Liber Ruber, the Ormond Deeds and the Kildare Rental – significantly add to our understand of both he and Mac Giolla Phádraig Osraí lineages, which to date have been muddled. New characters are uncovered, such as Morena ny Giolla Phádraig and her husband, John ‘the Blind’ Butler, and the previously ignored branch, Clann Maeleachlainn Ruadh. An account of the early stages of the Ormond-Mac Giolla Phádraig Osraí alliance, which would ultimately fragment the clan, is provided.
Colonial American Fitzpatrick Settlers Part I: Making Sense of One Line
by Ian Fitzpatrick and Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2020, 1, 18-39 (View this article)
Before the turn of the 17th century the settlement of Irish in the Americas lacked permanence. Soon after, Irish came to North America and the Caribbean in a steady flow, and by the mid 18th century a flood of Irish and Scotch-Irish had settled in the Americas. The reasons for that settlement were many and varied, as were the geographic origins and lineages of those Fitzpatricks among the influx. This article provides a review of the forces that pushed and pulled Irish and Scotch-Irish to the Americas. By way of example, a single Fitzpatrick line demonstrates how messy traditional genealogy of early Colonial American Fitzpatricks can get. That messiness is due in no small part to the cut and paste functionality at websites such as ancestry.com. But by careful review of authentic historical records, caution with speculative associations, and the power of Y-DNA analysis, it is possible to untangle the mess and bring back some much-needed clarity. In this article, the example used is that of the well-known colonial-settler William Fitzpatrick (born ca. 1690 AD), of Albemarle County, Virginia, who arrived in North American ca. 1728. Two living ancestors of William have been found to share a common ancestry from ca. 1650 AD; both bear a genetic mutation (FT15113) specific to William's line; this enables the ready identification of male descendants of William.
Mac Giolla Phádraig Osraí 1384-1534 AD, Part II
by Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2020, 1, 40-71 (View this article)
The starting place for Part II of Mac Giolla Phádraig Osraí: 1384-1534 is Feartach, Cill Chainnigh (Fertagh, Co. Kilkenny) where a previously little known Mac Giolla Phádraig cleric, and unrecognised clann chieftain, was appointed Prior in 1506. There are many mysterious elements of Kilpatrick’s tomb at Gráinseach Feartach (Grangefeartach), which is said to be the final resting place of Brian na luireach and his son Seán, and a critical examination of the tomb cannot fail to lead to the inevitable question – is it not they, but others, who are buried there?
In addition to the mysteries of Gráinseach Feartach, this article synthesises numerous entries in the Papal Registers, which provide clear evidence for a Mac Giolla Phádraig Osraí clerical lineage that enjoyed power, wealth, and influence, both within and without the clann. The exploits of the clerics, their relationship to other clann members, and their associations with their neighbours, are presented against the backdrop of the political landscape around Mac Giolla Phádraig Osraí country during the late fifteenth and early sixteenth centuries. The key players from the House of Ormond, and the House of Kildare, and their networks with Mac Giolla Phádraig Osraí of the era provide new insights into the clann’s leadership and lineages, which are more complex and extensive than previously understood.
Cover story: The Similar-Sounding Surnames of Haplogroup R-BY140757
by Dr Mike Fitzpatrick and Ian Fitzpatrick
Journal of the Fitzpatrick Clan Society 2021, 2, 1-41 (View this article)
Y-DNA analysis is a remarkable method that can inform patrilineal genealogies, both ancient, and modern. Applied here to facilitate a critical review of Branan pedigrees, an analysis of haplogroup R-BY140757 results in a deep questioning of the dominant narratives of the O’Braonáin Uí Dhuach (O’Brenan of Idough). What results is a disruption of those narratives that is total.
The O’Braonáin Uí Dhuach, held by Ossorian historians to share descent from Cearbhall, King of Osraí (843-888 AD), we argue, are not Osraighe, but are an Uí Failghi tribe – this based on the ultimate authority of Dubhaltach Mac Fhirbhisigh. Hence, Y-DNA connections between Branans, or those with similar-sounding surnames, and related others, are a false trail for those who claim descent from Cearbhall.
Once Mac Fhirbhisigh is embraced, and the erroneous pedigrees of the O’Braonáin Uí Dhuach are set aside, the origins of men with Branan, and similar-sounding surnames, of haplogroup R-BY140757, can be correctly determined. And, based on Y-DNA haplotype analysis, it is considered those origins are not with the O’Braonáin Uí Dhuach, or any Irish clan.
Rather, haplotype R-BY140757 appears to have originated from a family who settled near Braham, in Suffolk, after the Norman conquest of England. The key figure in the appearance of R-BY140757 pedigrees in Éire is Sir Robert de Braham, who was Sheriff of Kilkenny ca. 1250 AD.
Mac Giolla Phádraig Clerics 1394-1534 AD, Part I
by Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2021, 2, 42-65 (View this article)
Mac Giolla Phádraig Clerics 1394-1534 AD is a three-part series, which provides an account of all known individual Mac Giolla Phádraig clerics in the late medieval era and details their temporalities, occupations, familial associations, and broader networks. The ultimate goal of the series is the full contextualisation of all available historical records relating to Mac Giolla Phádraig clerics alongside the genealogical record that can be extracted by twenty-first century science – that being the science of Y-DNA.
The Papal Registers, in particular, record numerous occurrences of Mac Giolla Phádraig clerics, predominantly in the dioceses of Cill Dalua (Killaloe) and Osraí (Ossory), from the late fourteenth to the early sixteenth century. Yet, no small intrigue surrounds their emergence. Part I of Mac Giolla Phádraig Clerics 1394-1534 AD examines the context surrounding the earliest appointments of Mac Giolla Phádraig clerics, which is in neither Cill Dalua nor Osraí but the diocese of Luimneach (Limerick). Once that context is understood, a pattern of associations emerges.
A ‘coincidental’ twenty-first century surname match from the Fitzpatrick Y-DNA project leads to a review of the relationship between the FitzMaurice of Ciarraí (Kerry) clerics and Jordan Purcell, Bishop of Cork and Cloyne (1429-1472). The ‘coincidence’ then leads to an examination of a close Y-DNA match between men of the surnames Purcell and Hennessey. That match, coupled with the understanding that Nicholas Ó hAonghusa (O’Hennessey), elected Bishop of Lismore and Waterford (1480-1483) but with opposition, is considered a member of Purcell’s household, transforms the ‘coincidence’ into a curiosity.
Part I morphs into a conversation, likely uncomfortable for some, relating to clerical concubinage, illegitimacy, and the ‘lubricity’ of the prioress and her nuns at the Augustinian nunnery of St Catherine's O’Conyll. The nunnery was located at Mainistir na gCailleach Dubh (Monasternagalliaghduff), which lay just a stone’s throw from where Bishop Jordan Purcell and Matthew Mac Giolla Phádraig, the first Mac Giolla Phádraig cleric recorded in the Papal Registers, emerged.
Part I makes no judgments and draws no firm conclusions but prepares the reader for Part II by ending with some questions. Do the Mac Giolla Phádraig clerics of Osraí, who rose to prominence in the late-fifteenth century, have their origins in Deasmhumhain (Desmond)? Could the paternal lineages of Mac Giolla Phádraig clerics be, at least from the mid-fourteenth century, with the house of the Geraldine FitzMaurice clerics of Ciarraí? And, could some of the modern-day descendants of the Mac Giolla Phádraig clerics be those Costigans, FitzGeralds, and Fitzpatricks who are found under haplotype R-A1488?
Pátraic surnames in the Fiants and Patent Rolls of Ireland
Part 1: a method of approach to mega-data, and a Mac Caisín case study
by Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2021, 2, 66-92 (View this article)
The fiants and patent rolls of Ireland are an extraordinary and largely untapped source of information. This article taps into this valuable source with a focus on interrogating Pátraic-surnames, i.e., Patrick, Fitzpatrick, Kilpatrick, Mac Giolla Phádraig and Ó Maol Phádraig, which document grants, leases, and pardons, etc., issued under the Great Seal of Ireland. The extant records of fiants are for the period 1521-1603, and the patent rolls 1514-1575 and 1603-1633, i.e., much of the reign of Henry VIII of England to the eighth year of Charles I of England.
Ireland's fiants and patent rolls provide mega-data on names, places, occupations, relationships, and more, and Pátraic-surname records uncover rich narratives from all over Éire. Yet, there is a tendency for the vastness of the records to overwhelm, so a systematic approach is required to extract the maximum value. This article provides a method for 'eating an elephant', and one key is having a secure temporal frame of reference via which associations, familial and otherwise, can be understood.
By way of example, the surname Mac Caisín begins this series of articles on Pátraic surnames in the Fiants and Patent Rolls of Ireland. The choice of Mac Caisín may appear strange at first, since it is not obviously a Pátraic surname. However, this article argues the case study of Mac Caisín provides a clear example of how an interrogation of the fiants, and patents reveal many instances where members of Pátraic families are recorded by other names, such as Mac William, Mac Edmund, Mac Flynn and, maybe, Mac Caisín. Understanding such names in the fiants and patents requires a sound knowledge of context so they can be distinguished as surnames or patronymics. Still, even then, there is evidence that members of Pátraic families sometimes took other surnames due to, for example, fosterage or to 'mask' a clerical lineage.
This article seeks to answer questions about the Mac Caisín of Osraí (Ossory), who were unquestionably the close associates of the Fitzpatrick barons of Upper Ossory. Were the Mac Caisín either a lineage from an individual called Caisín (a name meaning curly-haired) Mac Giolla Phádraig, or a line out of fosterage, or of a ‘surname-masked’ clerical lineage; or, was there even any kinship bond?
Cover story: Mac Giolla Phádraig Dál gCais: an ancient clan rediscovered
by Dr Dan Fitzpatrick, Ian Fitzpatrick, and Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2022, 3, 1-45 (View this article)
Y-DNA analysis of Fitzpatricks has turned traditional historical narratives of how the surname was taken on its head. The attachment of the surname Fitzpatrick to the Barons of Upper Ossory, who were supposedly the descendants of Mac Giolla Phádraig Osraí and, in turn, of an ancient Laighin (Leinster) lineage, is no longer sustainable.
DNA insights and critical assessment of historical records have demonstrated that those who claim to descend from the barons have a Y-haplotype consistent with them emerging from a line of clerics out of a Norman-Irish origin ca. 1200 AD. Questions arise, therefore, regarding the origins of other large Fitzpatrick groups who, based on Y-DNA, can be shown to descend from ancient Irish. Could any of these lines descend from the Mac Giolla Phádraig Osraí of old, those of Annalistic fame?
For the first time, this article introduces the Mac Giolla Phádraig Dál gCais in a scholarly narrative. Mac Giolla Phádraig Dál gCais are, unquestionably, an ancient Pátraic surname clan. But are they also a Mac Giolla Phádraig lineage that arose in Osraí in ancient times? Such a question radically disrupts traditional narratives, yet the answer is ‘maybe’ – sound historical, genealogical and name occurrence evidence supports the view that there is no need to adhere to a singular patrimony for the Mac Giolla Phádraig Osraí and that a Dál gCais line was well positioned to have territory in Osraí and adopt Mac Giolla Phádraig as a surname.
With certainty, the Mac Giolla Phádraig who are the subject of this article are Dál gCais on a genetic basis since, via their paternal haplotype, they share common ancestry with Brian Bóruma, High King of Ireland. The descendants of those Mac Giolla Phádraig Dál gCais feature through ancient records for An Clár (Clare) are still found in the County, yet many derive from lines that were dispersed from their ancient An Clár homelands in the seventeenth-century. From An Clár to Oileáin Árann (Arann Islands), and Gaillimh (Galway), and – one way or another – on to Maigh Eo (Mayo), and Ros Comáin (Roscommon), they are a great and ancient Mac Giolla Phádraig Clan, who at times held much wealth, power, and influence.
And some were smugglers!
Letters from the Baron of Upper Ossory, and his son Sir Barnaby Fitzpatrick, AD 1571: Carrigan’s transcriptions
by Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2022, 3, 46-57 (View this article)
This article reproduces Rev. William Carrigan’s transcriptions of material he titled, ‘Letters from the Baron of Upper Ossory, and his son Sir Barnaby Fitzpatrick, AD 1571’. The letters are three pieces of correspondence from the Baron of Upper Ossory and one from Sir Barnaby to Sir William Fitzwilliam, Lord Justice of Ireland (1571-1575), and mainly relate to the baron’s various complaints — that he had lost castles and houses, lands and associated incomes, and goods, had been variously mistreated and was in exile, and that Sir Barnaby was culpable. The letters demonstrate the severe rift that had developed between the baron and his eldest legitimate son but also provide peripheral facts concerning the boron’s broader relationships, places of abode, and the timing of some of his life events.
Pátraic surnames in the Fiants and Patent Rolls of Ireland,Part II: The Mac Fynen of Upper Ossory
by Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2022, 3, 58-72 (View this article)
The Fiants and the Patent Rolls of Ireland are an extraordinary and largely untapped source of information. Part I of this series, which interrogates Pátraic-surnames in the fiants and patents, answered questions about the Mac Caisín of Osraí (Ossory), who were unquestionably the close associates of the Fitzpatrick barons of Upper Ossory. Traditionally considered a hereditary medical family, the Mac Caisín of Upper Ossory sprang from a hereditary clerical family or, more broadly, a hereditary learnèd family, whose origins were in the diocese of Cill Dalua (Killaloe). It is not implausible that the Mac Caisín were patrilineally connected with the Mac Giolla Phádraig Osraí but there is no evidence of such can be provided by either conventual genealogy or Y-DNA analysis.
In Part II, the spotlight falls on the Mac Fynen of Upper Ossory, and the approach follows that of Part I, i.e., securing a temporal frame of reference via which associations, familial and otherwise, can be understood, which affords some ability to distinguish name occurrences in the fiants and patents as either surnames or patronymics. And via the fiants, patents, and other records of the sixteenth and seventeenth centuries, it is possible to uncover, for the first time, that in many cases, Mac Fynen was, indeed, a surname that came to be used by those who had patrilineal origins with the Mac Giolla Phádraig of Ossory. The discovery of a second surname, not instantly recognisable as related to Mac Fynen but sharing the exact same patrilineal origins, further confirms the value the Fiants and Patents of Ireland have as source material for Pátraic surname research.
On Fitzpatrick Scholarship
Editorial by Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2022, 3, 73-77 (View this article)
The Mac Costigan of Ossory: dismantling an assumed genealogy
By Cynthia Costigan, Ian Fitzpatrick and Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2022, 3, 78-100 (View this article)
There is nothing new about the narratives of some Irish clans being sometimes inaccurate. But there is a world of difference between slight exaggerations of deeds, or misdeeds, or colourful embellishments of a character’s prowess, or a clan’s conquering status, and an entirely false clan narrative. Yet, a critical review of Clan Mac Costigan of Ossory reveals a origin narrative far from the traditional.
The dominant narrative of Clan Mac Costigan of Ossory over the past 140 or so years arrived in 1878 via Rev. John Shearman’s ‘Loca Patriciana’, in which he stated the Mac Costigan stemmed from ‘Oistegan’, a son of Seaffraid (Geoffrey) Mac Giolla Phádraig (d. 1269), who died in 1289. Sherman also stated that Oistegan’s son, Mac Oistegan, slew Thomas Butler, the First Baron Dunboyne, and 100 followers at Muileann gCearr, larmhí (Mullingar, Westmeath) in 1329. And so, the modern Mac Costigan narrative was born – yet it is an ‘assumed genealogy’, likely part inspired by Roger O’Farrells’s ‘Linea Antiqua’ (1709), and then encouraged along by the ever-unreliable John O’Hart.
But the attribution of Butler’s death to a Mac Costigan is hopelessly wrong. In addition, not a single ancient Mac Costigan pedigree exists. Rather, the Mac Costigan of Ossory arose in the mid-fifteenth century, as a Killaloe clerical lineage. And it is John Mac Costigan, who later took the alias Mac Giolla Phádraig, who takes centre stage in this article’s early stanzas.
The co-use of the surnames Mac Costigan and Mac Giolla Phádraig in fifteenth century Ossory is also captured in the current era because some Costigans and Fitzpatricks (formerly Mac Giolla Phádraig) share a common ancestry under haplotype R-A1488, and the Time to the Most Common Ancestor (TMRCA) of R-A1488 is ca. 1420. The TMRCA speaks to the very obvious, and it is impossible, based on either historical records or DNA analysis, to determine whether R-A1488 Fitzpatricks descend from a line of Mac Costigan, or vice versa. It is little wonder then, that throughout the sixteenth and seventeenth centuries, the Ossory land possessions of the Costigan, Fitzpatrick, and other kindred clans who had also adopted obscure aliases, such as the Mac Fynen (also known as Mac Kynen), notably in the Parish of Offerlane, were adjacent, interchanged, and shared. Here we dismantle the ‘assumed genealogy’ of the Mac Costigan of Ossory and posit an alternative based on robust genealogical research and twenty-first-century science.
Cover story: The Ó Maol Phádraig
by Ian Fitzpatrick and Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2023, 4, 1-10 (View this article)
Once upon a time, the Ó Maol Phádraig (O’Mulpatrick) was a notable clan; or, better – there were once notable clans of that name. Earlier, there were noteworthy individuals named Máel Pátraic, which is the earliest version of any name given to honour St Patrick. Among such notables were those whose given name came to transcend the individual – so, Máel Pátraic became attached to a patronym.
Our series of articles explores the name Máel Pátraic. In Part I, we discuss the origins of the name and consider the patterns apparent in early annalistic records. Connections are made to those regions of Éire where the name was commonly found. In Part II, we review authoritative Máel Pátraic genealogies, the dynasties whose members bore the name, and the emergence the Ó Maol Phádraig surname. In Part III, and we consider records that occur from the late medieval era until the nineteenth century. Finally, in Part IV, we link the living with those Ó Maol Phádraig gone before via the power of genetic genealogy.
Ó Maol Phádraig is a virtually extinct surname; today their descendants carry Fitzpatrick or other Pátraic-surname forms. Here, the name, the people, and the clans are revived.
A Similar-Sounding Surnames Sequel: Haplogroup R-FT70038
by John Maury Branan Jr
Journal of the Fitzpatrick Clan Society 2023, 4, 11-44 (View this article); (View Appendices)
Historical and Y-DNA analysis suggests that men with Branan and similar-sounding surnames of haplogroup R-BY140757 originated from the de Braham of Norman origin, who settled in Suffolk after the Norman conquest of England. Over the centuries, these de Braham took on important roles in English and Irish governance, military, and judiciaries. And in Ireland, the Norman surname took on, as was not uncommon, a Gaelic sound and written appearance, i.e., Branan and similar.
Descendants of Irish colonial settlers in Virginia with Branan-sounding surnames (Branham, Brannan, Brannon, etc.), who belong to the sub-haplogroup R-BY140757>FT70038, have been identified as the progeny of two notable eighteenth-century colonial North American settlers – Caron Brannon and Kenyon Branan.
This article identifies genealogical lines with known or hypothesized connections to Caron and Kenyon. Caron Brannon’s will indicates he had four sons, three of whom have direct male descendants documented and one documented to have died without children. Additionally, there are birth records for a fifth son, the eldest, who finds no mention in Caron’s will. Paper genealogy shows Kenyon Branan had one son with certainty, but three other lines are widely speculated to descend from him.
This project identified and recruited descendants from Caron’s and Kenyon’s lines for DNA testing. Y-DNA results for descendants of two well-documented sons of Caron Brannon form sub-haplogroups, R-FTC4333 and R-FT101136. This result is consistent with the hypothesis that Caron Brannon is the patriarch of R-FT70038. However, a striking new sub-haplogroup to R-FT70038, dubbed R-Y10443, was discovered matching two of the three lines previously thought to descend from Kenyon. The eldest son of Caron is shown as a possible father to Kenyon or as the patriarch of R-Y10443, but he cannot be both. This new insight suggests strongly that the patriarch of R-FT70038 was one to three generations prior to Caron Brannon and that Kenyon Branan plays a minor role in the lineages of the haplogroup.
The number of potential R-FT70038 haplotree options is now clearly defined. A combined analytical assessment of Y-SNP, Y-STR, and autosomal results reinforces the well-documented genealogies, debunks the speculative ones, and reveals new connections and chronologies that no single previous approach provided. Statistical modeling of the combined DNA data prefers the Haplotree with R-Y10433 descending directly from the patriarch and Kenyon Branan descending directly from Caron Brannon through his eldest son John.
Cover story: The Daltons of Kildalton
by Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2024, 5, 1-10 (View this article)
The Daltons of Kildalton (Cill an Dátúnaigh), a townland less than one mile north of the River Suir and the Co. Waterford (Port Láirge) border, are a well-known family with a rich and colourful history that has been documented back to fourteenth-century southern Co. Kilkenny (Cill Chainnigh). Such was the status of the family, who had Kilmodalla (Cill Modhallá) as one of their major bases from the fifteenth century, that by the sixteenth century the town had undergone a name change to Kildalton, forever embedding their patronymic in that place, and other areas nearby.
Part I of ‘The Daltons of Kildalton: a Norman-Irish gentry family’, focusses on the central family figure of the late thirteen-century, Richard de Antōn, who was Sheriff of Waterford between 1291 and 1293. Richard was almost certainly the forebear of the Daltons of Kildalton, and first established their place in Co. Kilkenny. Richard’s origins intrigue, as does his surname, but his place among the Irish gentry of the thirteenth century unequivocally connects him to families of high status and power, who came to Ireland (Éire) at the time of the Norman invasions.
Y-DNA analysis of ancestors of the Daltons of Kildalton is distinct and also intrigues. Yet, much sense can be made of a common genetic ancestry, ca. 1100 AD, with those of Branan-like surnames, whose ancestors also arrived in Ireland among the Norman gentry class.
The will of Thady Fitzpatrick, MD, 1674
by Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2023: S1, 1-10 (View this article)
The will of Thady Fitzpatrick MD (d. 1674) was transcribed by Rev. William Carrigan and is recorded among his notebooks, collectively known as the Carrigan Manuscripts. Carrigan made only a brief mention of Thady in The History and Antiquities of Diocese of Ossory, but his record of Thady’s will adds significantly to what is known of Thady’s family connections and land holdings. Notably, the will refers to Thady’s previously unknown brother, Florence, and four nephews. Moreover, among other notebooks, Carrigan recorded details of a family of Fitzpatricks in the parish of Rathdowney, possibly the descendants of Florence, brother of Thady Fitzpatrick MD.
The Pedigrees of the First Baron of Upper Ossory
by Dr Mike Fitzpatrick
Journal of the Fitzpatrick Clan Society 2023: S1, 11-26 (View this article)
The pedigrees of Brian Mac Giolla Phádraig (ca. 1478-1575), who was created the First Baron of Upper Ossory in 1541 and from whom emerged the line of later barons, feature prominently in several important publications relating to the Mac Giolla Phádraig Lords of Ossory. Pride of place among the pedigree authors goes to the renowned Ossory historian, Rev. William Carrigan (1860-1924), who he published his magnum opus, The History and Antiquities of the Diocese of Ossory, in 1905. Early in his research career, Carrigan adopted the position of two scholars who had gone before him, viz., Dr John O’Donovan and Rev. John Shearman, notably, that Brian’s father was Brian na Luireach (i.e., ‘of the coats of mail’) Mac Giolla Phádraig. However, by 1922, toward the end of his life, Carrigan’s opinion had changed, and he came to the position that the father of the first baron was not Brian na Luireach, but Seaán Mac Giolla Phádraig. Here, a review of Carrigan’s Manuscripts reveals his research journey to uncover the true identity of Brian’s father.