Irish Pedigrees or the Origin and Stem of the Irish Nation By John O'Hart
The descent of the Irish Celts from Adam
1. Adam
2. Seth
3. Enos
4. Cainan
5. Mahalaleel
6. Jared
7. Enoch
8. Methuselah
9. Lamech
10. Noah divided the world amongst his three sons, begotten of his wife Titea: viz., to Shem he gave Asia, within the Euphrates, to the Indian Ocean; to Ham he gave Syria, Arabia, and Africa; and to Japhet, the rest of Asia beyond the Euphrates, together with Europe to Gadea (or Cadiz).
11. Japhet was the eldest son of Noah. He had fifteen sons, amongst whom he divided Europe and the part of Asia which his father had allotted to him.
12. Magog: From whom descended the Parthians, Bactrians, Amazons, etc.; Parthalon, the first planter of Ireland, about three hundred years after the Flood; and also the rest of the colonies that planted there, viz., the Nemedians, who planted Ireland, Anno Mundi three thousand and forty-six, or three hundred and eighteen years after the birth of Abraham, and two thousand one hundred and fifty-three years before Christ. The Nemedians continued in Ireland for two hundred and seventeen years; within which time a colony of theirs went into the northern parts of Scotland, under the conduct of their leader Briottan Maol, from whom Britain takes its name, and not from "Brutus," as some persons believed. From Magog were also descended the Belgarian, Belgian, Firbolgian or Firvolgian colony that succeeded the Nemedians, Anno Mundi, three thousand two hundred and sixty-six, and who first erected Ireland into a Monarchy. [According to some writers, the Fomorians invaded Ireland next after the Nemedians.] This Belgarian of Firvolgian colony continued in Ireland for thirty-six years, under nine of their Kings; when they were supplanted by the Tuatha-de-Danann (which means, according to some authorities, "the people of the god Dan," whom they adored), who possessed Ireland for one hundred and ninety-seven years, during the reigns of nine of their kings; and who were then conquered by the Gaelic, Milesian, or Scotic Nation (the three names by which the Irish people were known), Anno Mundi three thousand five hundred. This Milesian or Scotic Irish Nation possessed and enjoyed the Kingdom of Ireland for two thousand eight hundred and eighty-five years, under one hundred and eighty-three Monarchs; until their submission to King Henry the Second of England, Anno Domini one thousand one hundred and eighty-six.
13. Boath, one of the sons of Magog; to whom Scythia came as his lot, upon the division of the Earth by Noah amongst his sons, and by Japhet of his part thereof amongst his sons.
14. Phoeniusa Farsaidh (or Fenius Farsa) was King of Scythia, at the time when Ninus ruled the Assyrian Empire; and, being a wise man and desirous to learn the languages that not long before confounded the builders of the Tower of Babel, employed able and learned men to go among the dispersed multitude to learn their several languages; who sometime after returning well skilled in what they went for, Phœniusa Farsaidh erected a school in the valley of Senaar, near the city of Æothena, in the forty-second year of the reign of Ninus; whereupon, having continued there with his younger son Niul for twenty years, he returned home to his kingdom, which, at his death, he left to the oldest son Nenuall; leaving to Niul no other patrimony than his learning and the benefit of the said school.
15. Niul, after his father returned to Scythia, continued some time at œothena, teaching the languages and other laudable sciences, until upon report of his great learning he was invited into Egypt by Pharaoh, the King; who gave him the land of Campus Cyrunt, near the Red Sea to inhabit, and his daughter Scota in marriage; from whom their posterity are ever since called Scots; but, according to some annalists, the name "Scots" is derived from the word Scythia. It was this Niul that employed Gaodhal [Gael], son of Ethor, a learned and skilful man, to compose or rather refine and adorn the language, called Bearla Tobbai, which was common to all Niul's posterity, and afterwards called Gaodhilg (or Gaelic), from the said Gaodhal who composed or refined it; and for his sake also Niul called his own eldest son "Gaodhal."
16. Gaodhal (or Gathelus), the son of Niul, and ancestor of Clan-na-Gael, that is, "the children or descendants of Gaodhal". In his youth this Gaodhal was stung in the neck by a serpent, and was immediately brought to Moses, who, laying his rod upon the wounded place, instantly cured him; whence followed the word "Glas" to be added to his named, as Gaodhal Glas (glas: Irish, green; Lat. glaucus; Gr. glaukos), on account of the green scar which the word signifies, and which, during his life, remained on his neck after the wound was healed. And Gaodhal obtained a further blessing, namely-that no venomous beast can live any time where his posterity should inhabit; which is verified in Creta or Candia, Gothia or Getulia, Ireland, etc. The Irish chroniclers affirm that from this time Gaodhal and his posterity did paint the figures of Beasts, Birds, etc., on their banners and shields, to distinguish their tribes and septs, in imitation of the Israelites; and that a "Thunderbolt" was the cognisance in their chief standard for many generations after this Gaodhal.
17. Asruth, after his father's death, continued in Egypt and governed his colony in peace during his life.
18. Sruth, soon after his father's death, was set upon by the Egyptians, on account of their former animosities towards their predecessors for having taken part with the Israelites against them; which animosities until then lay raked up in the embers, and now broke out in a flame to that degree, that after many battles and conflicts wherein most of his colony lost their live, Sruth was forced with the few remaining to depart the country; and, after many traverses at sea, arrived at the Island of Creta (now called Candia), where he paid his last tribute to nature.
19. Heber Scut (scut: Irish, a Scot), after his father's death and a year's stay in Creta, departed thence, leaving some of his people to inhabit the Island, where some of their posterity likely still remain; "because the Island breeds no venomous serpent ever since." He and his people soon after arrived in Scythia; where his cousins, the posterity of Nenuall (eldest son of Fenius Farsa, above mentioned), refusing to allot a place of habitation form him and his colony, they fought many battles wherein Heber (with the assistance of some of the natives who were ill-affected towards their king), being always victor, he at length forced the sovereignty from the other, and settled himself and his colony in Scythia, who continued there for four generations. (Hence the epithet Scut, "a Scot" or "a Scythian," was applied to this Heber, who was accordingly called Heber Scot.) Heber Scot was afterwards slain in battle by Noemus the former king's son.
20. Baouman;
21 Ogaman; and
22. Tait, were each kings of Scythia, but in constant war with the natives; so that after Tait's death his son,
23. Agnon and his followers betook themselves to sea, wandering and coasting upon the Caspian Sean for several (some say seven) years in which time he died.
24. Lamhfionn and his fleet remained at sea for some time, after his father's death, resting and refreshing themselves upon such islands as they met with. It was then the Cachear, their magician or Druid, foretold that there would be no end of their peregrinations and travel until they should arrive at the Western Island of Europe, now called Ireland, which was the place destined for their future and lasting abode and settlement; and that not they but their posterity after three hundred years should arrive there. After many traverses of fortune at sea, this little fleet with their leader arrived at last and landed at Gothia or Geulia-more recently called Lybia, where Carthage was afterwards built; and, soon after, Lamhfionn died there.
25. Heber Glunfionn was born in Gothia, where he died. His posterity continued there to the eighth generation; and were kings or chief rulers there for one hundred and fifty years-some say three hundred years.
26 Agnan Fionn;
27. Febric Glas;
28. Nenuall;
29. Nuadhad;
30. Alladh;
31. Arcadh; and
32. Deag: of these nothing remarkable is mentioned, but that they lived and died kings in Gothia or Getulia.
33. Brath was born in Gothia. Remembering the Druid's prediction, and his people having considerably multiplied during their abode in Geulia, he departed thence with a numerous fleet to seek out the country destined for their final settlement, by the prophecy of Cachear, the Druid above mentioned; and, after some time, he landed upon the coast of Spain, and by strong hand settled himself and his colony in Galicia, in the north of that country.
34. Breoghan (or Brigus) was king of Galicia, Andalusia, Murcia, Castile, and Portugal-all of which he conquered. He built Breoghan's Tower or Brigantia in Galicia, and the city of Brigantia or Braganza in Portugal-called after him; and the kingdom of Castile was then also called after him Brigia. It is considered that "Castile" itself was so called from the figure of a castle which Brigus bore for his Arms on his banner. Brigus sent a colony into Britain, who settled in that territory now known as the counties of York, Lancaster, Durham, Westmoreland, and Cumberland, and, after him were called Brigantes; whose posterity gave formidable opposition to the Romans, at the time of the Roman invasion of Britain.
35. Bilé; was king of those countries after his father's death; and his son Galamh [galav] or Milesius succeeded him. This Bilé had a brother named Ithe.
36. Milesius, in his youth and in his father's life-time, went into Scythia, where he was kindly received by the king of that country, who gave him his daughter in marriage, and appointed him General of his forces. In this capacity Milesius defeated the king's enemies, gained much fame, and the love of all the king's subjects. His growing greatness and popularity excited against him the jealousy of the king; who, fearing the worst, resolved on privately dispatching Milesius our of the way, for, openly, he dare not attempt it. Admonished of the king's intentions in his regard, Milesius slew him; and thereupon quitted Scythia and retired into Egypt with a fleet of sixty sail. Pharaoh Nectonibus, then king of Egypt, being informed of his arrival and of his great valour, wisdom, and conduct in arms, made him General of all his forces against the king of Ethiopia then invading his country. Here, as in Scythia, Milesius was victorious; he forced the enemy to submit to the conqueror's own terms of peace. By these exploits Milesius found great favour with Pharaoh, who gave him, being then a widower, his daughter Scota in marriage; and kept him eight years afterwards in Egypt. During the sojourn of Milesius in Egypt, he employed the most ingenious and able persons among his people to be instructed in the several trades, arts, and sciences used in Egypt; in order to have them taught to the rest of his people on his return to Spain. [The original name of Milesius of Spain was "Galamh" (gall: Irish, a stranger; amh, a negative affix), which means, no stranger: meaning that he was no stranger in Egypt, where he was called "Milethea Spaine," which was afterwards contracted to "Miló Spaine" (meaning the Spanish Hero), and finally to "Milesiius" (mileadh: Irish, a hero; Lat. miles, a soldier).] At length Milesius took leave of his father-in-law, and steered towards Spain; where he arrived to the great joy and comfort of his people; who were much harassed by the rebellion of the natives and by the intrusion of other foreign nations that forced in after his father's death, and during his own long absence from Spain. With these and those he often met; and, in fifty-four battles, victoriously fought, he routed, destroyed, and totally extirpated them out of the country, which he settled in peace and quietness. In his reign a great dearth and famine occurred in Spain, of twenty-six years' continuance, occasioned, as well by reason of the former troubles which hindered the people from cultivating, and manuring the ground, as for want of rain to moisten the earth - but Milesius superstitiously believed the famine to have fallen upon him and his people as a judgment and punishment from their gods, for their negligence in seeking out the country destined for their final abode, so long before foretold by Cachear their Druid or magician, as already mentioned - the time limited by the prophecy for the accomplishment thereof being now nearly, if not fully, expired. To expiate his fault and to comply with the will of his gods, Milesius, with the general approbation of his people, sent his uncle Ithe, with his son Lughaidh [Luy], and one hundred and fifty stout men to bring them an account of those western islands; who, accordingly, arriving at the island since then called Ireland, and landing in that part of it now called Munster, left his son with fifty of his men to guard the ship, and with the rest travelled about the island. Informed, among other things, that the three sons of Cearmad, called Mac-Cuill, MacCeacht, and MacGreine, did then and for thirty years before rule and govern the island, each for one year, in his turn; and that the country was called after the names of their three queens - Eire, Fodhla, and Banbha, respectively: one year called "Eire," the next "Fodhla," and the next "Banbha," as their husbands reigned in their regular turns; by which names the island is ever since indifferently called, but most commonly "Eire," because that MacCuill, the husband of Eire, ruled and governed the country in his turn the year that the Clan-na-Milé (or the sons of Milesius) arrived in and conquered Ireland. And being further informed that the three brothers were then at their palace at Aileach Neid, in the north part of the country, engaged in the settlement of some disputes concerning their family jewels, Ithe directed his course thither; sending orders to his son to sail about with his ship and the rest of his men, and meet him there. When Ithe arrived where the (Danann) brothers were, be was honourably received and entertained by them; and, finding him to be a mail of great wisdom. and knowledge, they referred their disputes to him for decision. That decision having met their entire satisfaction, Ithe exhorted them to mutual love, peace, and forbearance; adding much in praise of their delightful, pleasant, and fruitful country; and then took his leave, to return to his ship, and go back to Spain. No sooner was he gone than the brothers; began to reflect on the high commendations which Ithe gave of the Island; and, suspecting his design of bringing others to invade it, resolved to prevent them, and therefore pursued him with a strong party, overtook him, fought and routed his men and wounded himself to death (before his son or the rest of his men left on ship-board could come to his rescue) at a place called, from that fight and his name, Magh Ithe or "The plain of Ithe" (an extensive plain in the barony of Raphoe, county Donegal); whence his son, having found him in that condition, brought his dead and mangled body back into Spain, and there exposed it to public view, thereby to excite his friends and relations to avenge his murder. [Note: that all the invaders and planters of Ireland, namely, Parthalonians, Neimhedh, the Firbolgs, Tuatha-de-Danann, and Clan-na-Milé, where originally Scythians, of the line of Japbet, who had the language called Bearla-Tobbai or Gaoidhilg [Gaelic] common amongst them all; and consequently not to be wondered at, that Ithe and the Tuatha-de-Danann understood one another without an Interpreter - both speaking the same language, though perhaps with some difference in the accent]. The exposing of the dead body of Ithe had the desired effect; for, thereupon, Milesius made great preparations in order to invade Ireland - as well to avenge his uncle's death, as also in obedience to the will of his gods, signified by the prophecy of Cachear, aforesaid. But, before he could effect that object, he died, leaving the care, and charge of that expedition upon his eight legitimate sons by his two wives before mentioned. Milesius was a very valiant champion, a great warrior, and fortunate and prosperous in all his undertakings: witness his name of "Milesius," given him from the many battles (some say a thousand, which the word "Milé" signifies in Irish as well as in Latin) which he victoriously fought and won, as well in Spain, as in all the other countries and kingdoms be traversed in his younger days. The eight brothers were neither forgetful nor negligent in the execution of their father's command; but, soon after his death, with a numerous fleet well manned and equipped, set forth from Breoghan's Tower or Brigantia (now Corunna) in Galicia, in Spain, and sailed prosperously to the coasts of Ireland or lnis-Fail, where they met many difficulties and various chances before they could land: occasioned by the diabolical arts, sorceries, and enchantments used by the Tuatha-de-Danann, to obstruct their landing; for, by their magic art, they enchanted the island so as to appear to the Milesians or Clan-na-Milé in the form of a Hog, and no way to come at it (whence the island, among the many other names it had before, was called "Muc-Inis or "The Hog Island"); and withal raised so great a storm, that the Milesian fleet was thereby totally dispersed and many of them cast away, wherein five of the eight brothers, sons of Milesius, lost their lives. That part of the fleet commanded by Heber, Heremon, and Amergin (the three surviving, brothers), and Heber Donn, son of Ir (one of the brothers lost in the storm), overcame all opposition, landed safe, fought and routed the three Tuatha-de Danann Kings at Slieve-Mis, and thence pursued and overtook them at Tailten, where another bloody battle was fought; wherein the three (Tuatha-de-Danann) Kings and their Queens were slain, and their army utterly routed and destroyed: so that they could never after give any opposition to the Clan-na-Milé in their new conquest; who, having thus sufficiently avenged the death of their great uncle Ithe, gained the possession of the country foretold them by Cachear, some ages past, as already mentioned. Heber and Heremon, the chief leading men remaining of the eight brothers, sons of Milesius aforesaid, divided the kingdom between them (allotting a proportion of land to their brother Amergin, who was their Arch-priest, Druid, or magician; and to their nephew Heber Donn, and to the rest of their chief commanders), and became jointly the first of one hundred and eighty-three Kings or sole Monarchs of the Gaelic, Milesian, or Scottish Race, that ruled and governed Ireland, successively, for two thousand eight hundred and eighty-five years from the first year of their reign), Anno Mundi three thousand five hundred, to their submission to the Crown of England in the person of King Henry the Second; who, being also of the Milesian Race by Maude, his mother, was lineally descended from Fergus Mór MacEarca, first King of Scotland, who was descended from the said Heremon - so that the succession may be truly said to continue in the Milesian Blood from before Christ one thousand six hundred and ninety-nine years down to the present time. Heber and Heremon reigned jointly one year only, when, upon a difference between their ambitious wives, they quarrelled and fought a battle at Ardeath or Geshill (Geashill, near Tullamore in the King's County), where Heber was slain by Heremon; and, soon after, Amergin, who claimed an equal share in the government, was, in another battle fought between them, likewise slain by Heremon. Thus, Heremon became sole Monarch, and made a new division of the land amongst his comrades and friends, viz.: the south part, now called Munster, he gave to his brother Heber's four sons, Er, Orba, Feron, and Fergna; the north part, now Ulster, he gave to Ir's only son Heber Donn; the east part or Coigeadh, Galian, now called Leinster, be gave to Criomthann-sciath-bheil, one of his commanders; and the west part, now called Connaught, Heremon gave to Un-Mac-Oigge, another of his commanders; allotting a part of Munster to Lughaidh (the son of Ithe, the first Milesian discoverer of Ireland), amongst his brother Heber's sons. From these three brothers, Heber, Ir, and Heremon (Amergin dying without issue), are descended all the Milesian Irish of Ireland and Scotland, viz.: from Heber, the eldest brother, the provincial Kings of Munster (of whom thirty-eight were sole Monarchs of Ireland), and most of the nobility and gentry of Munster, and many noble families in Scotland, are descended. From Ir, the second brother, all the provincial Kings of Ulster (of whom twenty-six were sole Monarchs of Ireland), and all the ancient nobility and gentry of Ulster, and many noble families in Leinster, Munster, and Connaught, derive their pedigrees; and, in Scotland, the Clan-na-Rory - the descendants of an eminent man, named Ruadhri or Roderick, who was Monarch of Ireland for seventy years (viz., from Before Christ 288 to 218). From Heremon, the youngest of the three brothers, were descended one hundred and fourteen sole Monarchs of Ireland: the provincial Kings and Hermonian nobility and gentry of Leinster, Connaught, Meath, Orgiall, Tirowen, Tirconnell, and Clan-na-boy; the Kings of Dalriada; all the Kings of Scotland from Fergus Mór MacEarea, down to the Stuarts; and the Kings and Queens of England from Henry the Second down to tile present time. The issue of Ithe is not accounted among the Milesian Irish or Clan-na-Milé, as not being descended from Milesius, but from his uncle Ithe; of whose posterity there were also some Monarchs of Ireland (see Roll of the Irish Monarchs, infra), and many provincial or half provincial Kings of Munster: that country upon its first division being allocated to the sons of Heber and to Lughaidh, son of Ithe, whose posterity continued there accordingly. This invasion, conquest, or plantation of Ireland by the Milesian or Scottish Nation took place in the Year of the World three thousand Ova hundred, or the next year after Solomon began the foundation of the Temple of Jerusalem, and one thousand six hundred and ninety-nine years before the Nativity of our Saviour Jesus Christ; which, according to the Irish computation of Time, occurred Anno Mundi five thousand one hundred and ninety-nine: therein agreeing with the Septuagint, Roman Martyrologies, Eusebius, Orosius, and other ancient authors; which computation the ancient Irish chroniclers exactly observed in their Books of the Reigns of the Monarchs of Ireland, and other Antiquities of that Kingdom ; out of which the Roll of the Monarchs of Ireland, from the beginning of the Milesian Monarchy to their submission to King Henry the Second of England, a Prince of their own Blood, is exactly collected. [As the Milesian invasion of Ireland took place the next year after the laying of the foundation of the Temple of Jerusalem by Solomon, King of Israel, we may infer that Solomon was contemporary with Milesius of Spain; and that the Pharaoh King of Egypt, who (1 Kings iii. 1,) gave his daughter in marriage to Solomon, was the Pharaoh who conferred on Milesius of Spain the hand of another daughter Scota.] Milesius of Spain bore three Lions in his shield and standard, for the following reasons; namely, that, in his travels in his younger days into foreign countries, passing through Africa, he, by his cunning and valour, killed in one morning three Lions; and that, in memory of so noble and valiant an exploit, he always after bore three Lions on his shield, which his two surviving sons Heber and Heremon, and his grandson Heber Donn, son of Ir, after their conquest of Ireland, divided amongst them, as well as they did the country: each of them. bearing a Lion in his shield and banner, but of different colours; which the Chiefs of their posterity continue to this day: some with additions and differences; others plain and entire as they had it from their ancestors.
The Celts of Ireland descend from three sons of Milesius, (37-1 Heremon, 37-2 Heber and 37-3 Ir) and from his uncle (35-1 Ithe)

1 "Irish Pedigrees or the Origin and Stem of the Irish Nation", by John O'Hart is one of the best known Irish genealogical publications in the world. The first edition appeared in 1876, but was followed by several subsequent editions that added greatly to the overall size of the work. The most quoted edition was published in New York in 1923, twenty years after the author's death. It is worth mentioning here that the original work did not include and heraldic (coat of arms) information and that this was added to posthumous publications by unscrupulous publishers, presumably to increase sales. In general, O'Hart is a dubious source, at best, for such information (see quote below from Edward MacLysaght in regard to this topic).
John O'Hart was born in Crossmolina, Co. Mayo, in 1824. He received an excellent education with the intention of joining the priesthood. However, he instead spent two years in the constabulary (the police), after which he was employed by the Commissioners of National Education in Ireland from 1845, the first year of the Famine. He became an Associate in Arts at the Queen's University, and thereafter he was an active member of several scholarly societies. He was an avid genealogist and took a keen interest in Irish history, despite never receiving formal training as an historian. Politically he was an Irish nationalist, and in religious matters, a committed Catholic. Both of these factors permeated his work. He died in 1902 in Clontarf, Co. Dublin, at the age of 78.
O'Hart used many sources to compile the information that appears in his major work. His principal sources were Gaelic genealogies, like those of O'Clery, MacFirbis and O'Farrell. Along with the Gaelic annals, especially the Annals of the Four Masters, O'Hart was able to 'reconstruct' the medieval and ancient pedigrees that appear here. He also used later sources, like the works of Burke, Collins, Harris, Lodge and Ware to extend these lineages into the eighteenth and nineteenth centuries. But arguably the most important information contained in these genealogies came where O'Hart gathered the details directly from the families concerned, often from private papers or family tradition. These sections concern the later period, particularly post 1800, and are good for many specific localities like western Co. Clare.
There are two types of genealogies in O'Hart; the genealogies of the Gaelic families and the genealogies of Anglo-Norman and other later settlers. O'Hart made one important distinction in his treatment of these. Irish mythology records that every family was descended from a certain Milesius of Spain who in about 1700 BC led his followers to invade and conquer Ireland. The Christian monks who wrote these genealogies down in the 9th century, 2,500 years after Milesius, also added their own beliefs. So they recorded that Milesius was the 36th in descent from Adam! O'Hart, being both an ardent believer in the Gaelic myths and Christianity, followed their example. In his Gaelic genealogies a number representing the generation of descent from Adam precedes every generation. By contrast the Anglo-Normans and later invaders made no such claims, so O'Hart's genealogies of these families do not include these numbers. O'Hart showed, probably incorrectly, that every Gaelic family was descended from four of Milesius's family. These were his three sons, Heber, Ir and Heremon, and his uncle Ithe. These four were considered the 'stem' lines of the genealogies that followed.
While he undertook a great deal of research, using the majority of available published sources, many Gaelic scholars have superseded his work over the last 100 years. He was not familiar with the abundant unpublished Gaelic manuscript sources available. These have shown that many of his genealogies are incorrect for the years prior to 1600 AD. Furthermore, O'Hart was not a professional historian or genealogist, and had little training in using the esoteric sources he consulted. As a consequence he misunderstood a great deal about Gaelic society and culture, a world which had largely disappeared from Ireland long before he put pen to paper. He was also credulous in using the sources he did consult, believing that the myths were fact.
Despite these limitations, careful use of his work can be very productive. His genealogies for the years after 1600 have great value, and are often unavailable elsewhere. He was also able to consult many sources which have since been destroyed or lost. In the words of Edward MacLysaght, Ireland's most famous authority on the history of surnames, he 'made use of it almost daily'.
In relation to O'Hart and other similar publications, MacLysaght, however, also warns:
"The subject of Irish families is one in which much interest is evinced, but the popular books usually consulted and regarded as authoritative, particularly in America, are in fact unreliable. The inaccurate and misleading information thus imparted with cumulative effect is, however, much more deplorable in the armorial [coats of arms] sphere than in the genealogical. It is an indisputable fact that the publication presenting colour plates of Irish arms which is probably most widely consulted is no less than seventy per cent inaccurate, not only in mere detail, but often in points of primary importance and of an elementary kind. Apart from their many grotesque heraldic blunders the compilers of this work seem to have had a sort of rule of thumb; if they could not find arms for one Irish sept they looked for the name of another somewhat resembling it in sound: thus, for example, they coolly assigned the arms of Boylan to Boland. This frequently resulted in the arms of some purely English family being inserted in their book of "Irish Arms" the Saxon Huggins being equated with O'Higgins, and so on. When this arbitrary method failed them they fell back on the arms of some great Irish sept. To quote one instance of this: Gleeson, Noonan and McFadden are all given the arms of O'Brien, though none of these septs had any connexion whatever with the O'Briens or with each other. Consequently many Americans of Irish descent are in good faith using erroneous and often English arms derived from the spurious source in question.
A certain cachet has been given to this because, in the more recent editions of O'Hart's Irish Pedigrees, these same coloured plates have been inserted as if they were an integral part of O'Hart's book. The serious genealogist uses O'Hart with caution, if at all, for he is a far from reliable authority except for the quite modern period. John O'Hart, however, undoubtedly did a vast amount of research, no matter how he used the information he acquired: I know that some of these errors of ascription can actually be traced to him, but it is surely an injustice to him that his well-known name should be used as a cover for the propagation of false and often ludicrous heraldic statements."