John O'Hart (; 1824–1902) was an Irish historian and

genealogist Genealogy () is the study of families, family history, and the tracing of their Lineage (anthropology), lineages. Genealogists use oral interviews, historical records, genetic analysis, and other records to obtain information about a family ...

. He is noted for his work on ancient Irish lineage. He was born in Crossmolina, County Mayo, Ireland. A committed

Roman Catholic The Catholic Church (), also known as the Roman Catholic Church, is the largest Christian church, with 1.27 to 1.41 billion baptized Catholics worldwide as of 2025. It is among the world's oldest and largest international institut ...

and

Irish nationalist Irish nationalism is a nationalist political movement which, in its broadest sense, asserts that the people of Ireland should govern Ireland as a sovereign state. Since the mid-19th century, Irish nationalism has largely taken the form of cult ...

, O'Hart had originally planned to become a priest but instead spent two years as a police officer. He was an

Associate in Arts An associate degree or associate's degree is an undergraduate degree awarded after a course of post-secondary study lasting two to three years. It is a level of academic qualification above a high school diploma and below a bachelor's degree. ...

at the

Queen's University, Belfast The Queen's University of Belfast, commonly known as Queen's University Belfast (; abbreviated Queen's or QUB), is a public research university in Belfast, Northern Ireland, United Kingdom. The university received its charter in 1845 as part of ...

. He worked at the Commissioners of National Education during the years of the Great Famine. He worked as a genealogist and took an interest in Irish history. He died in 1902 in Clontarf near

Dublin Dublin is the capital and largest city of Republic of Ireland, Ireland. Situated on Dublin Bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, and is bordered on the south by the Dublin Mountains, pa ...

, at the age of 78. O'Hart's 800-page, ''The Irish and Anglo-Irish landed gentry'' (Dublin 1884), was reprinted in 1969, with an introduction by

Edward MacLysaght Edgeworth Lysaght, later Edward Anthony Edgeworth Lysaght, and from 1920 Edward MacLysaght (; 6 November 1887 – 4 March 1986) was a genealogist of twentieth-century Ireland. His numerous books on Irish surnames built upon the work of Rev. Pat ...

, the first Chief Herald of Ireland. Another work, ''Irish pedigrees; or, The origin and stem of the Irish nation'', first published in 1876, has come out in several subsequent editions. To complete his genealogies he used the writings of Cú Choigcríche Ó Cléirigh, Dubhaltach Mac Fhirbhisigh and O'Farrell, along with the ''

Annals of the Four Masters The ''Annals of the Kingdom of Ireland'' () or the ''Annals of the Four Masters'' () are chronicles of Middle Ages, medieval Irish history. The entries span from the Genesis flood narrative, Deluge, dated as 2,242 Anno Mundi, years after crea ...

'', for the medieval pedigrees. He used the works of

Bernard Burke Sir John Bernard Burke, (5 January 1814 – 12 December 1892) was a British genealogist and Ulster King of Arms, who helped publish ''Burke's Peerage''. Personal life Burke, of Irish descent, was born at London and was educated in London an ...

, John Collins and others to extend his genealogies past the 17th century.

Stem of the Irish nation

In his ''Irish Pedigrees'', O'Hart presents the legendary origins of the Irish people, from the Biblical Adam and Eve through the kings of ancient

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

. Irish tradition holds that every Irish person is descended from the king Milesius who emigrated from

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

in approximately 1700 BC, according to the ''

''. O'Hart started each of his genealogies with

Adam Adam is the name given in Genesis 1–5 to the first human. Adam is the first human-being aware of God, and features as such in various belief systems (including Judaism, Christianity, Gnosticism and Islam). According to Christianity, Adam ...

, recording Milesius as his 36th descendant. From the start;
(1)

, his son
(2)

Seth Seth, in the Abrahamic religions, was the third son of Adam and Eve. The Hebrew Bible names two of his siblings (although it also states that he had others): his brothers Cain and Abel. According to , Seth was born after Abel's murder by Cain, ...

, his son
(3) Enos, his son
(4) Cainan, his son
(5) Mahalaleel, his son
(6)

Jared Jared is a given name of Bible, Biblical derivation. Origin In the Book of Genesis, the Jared (biblical figure), biblical patriarch Jared () was the sixth in the ten pre-Noah's Ark, flood generations between Adam and Noah; he was the son of Maha ...

, his son
(7)

Enoch Enoch ( ; ''Henṓkh'') is a biblical figure and Patriarchs (Bible), patriarch prior to Noah's flood, and the son of Jared (biblical figure), Jared and father of Methuselah. He was of the Antediluvian period in the Hebrew Bible. The text of t ...

, his son
(8)

Methuselah Methuselah (; ''Məṯūšélaḥ'', in pausa ''Məṯūšālaḥ'', "His death shall send" or "Man of the javelin" or "Death of sword"; ''Mathousalas'') was a biblical patriarch and a figure in Judaism, Christianity, and Islam. He is clai ...

, his son
(9) Lamech, his son
(10)

Noah Noah (; , also Noach) appears as the last of the Antediluvian Patriarchs (Bible), patriarchs in the traditions of Abrahamic religions. His story appears in the Hebrew Bible (Book of Genesis, chapters 5–9), the Quran and Baháʼí literature, ...

, his son
(11)

Japhet Japheth ( ''Yép̄eṯ'', in pausa ''Yā́p̄eṯ''; '; ; ') is one of the three sons of Noah in the Book of Genesis, in which he plays a role in the story of Noah's drunkenness and the curse of Ham, and subsequently in the Table of Nations ...

, his son
(12) Magog, his son
(13) Baoth, "to whom

Scythia Scythia (, ) or Scythica (, ) was a geographic region defined in the ancient Graeco-Roman world that encompassed the Pontic steppe. It was inhabited by Scythians, an ancient Eastern Iranian equestrian nomadic people. Etymology The names ...

came has his lot", his son
(14) Phoeniusa Farsaidh ( Fenius Farsa) King of Scythia, his son
(15) Niul, his son
(16) Gaodhal (Gathelus), his son
(17) Asruth, his son
(18) Sruth (who fled

Egypt Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northe ...

to Creta), his son
(19) Heber Scut (returned to Scythia), his son
(20) Beouman, King of Scythia, his son
(21) Ogaman King of Scythia, his son
(22) Tait King of Scythia, his son
(23) Agnon (who fled Scythia by sea with the majority of his people), his son
(24) Lamhfionn (who led his people to Gothia or Getulia, where

Carthage Carthage was an ancient city in Northern Africa, on the eastern side of the Lake of Tunis in what is now Tunisia. Carthage was one of the most important trading hubs of the Ancient Mediterranean and one of the most affluent cities of the classic ...

was afterwards built), his son
(25) Heber Glunfionn, King of Gothia, his son
(26) Agnan Fionn King of Gothia, his son
(27) Febric Glas King of Gothia, his son
(28) Nenuall King of Gothia, his son
(29) Nuadhad King of Gothia, his son
(30) Alladh King of Gothia, his son
(31) Arcadh King of Gothia, his son
(32) Deag King of Gothia, his son
(33) Brath, King of Gothia (who left Gothia with a large band of his people and settled in Galicia,

), his son
(34) Breoghan, King of Galicia,

Andalusia Andalusia ( , ; , ) is the southernmost autonomous communities of Spain, autonomous community in Peninsular Spain, located in the south of the Iberian Peninsula, in southwestern Europe. It is the most populous and the second-largest autonomou ...

Murcia Murcia ( , , ) is a city in south-eastern Spain, the Capital (political), capital and most populous city of the autonomous community of the Region of Murcia, and the Ranked lists of Spanish municipalities#By population, seventh largest city i ...

, Castile, and

Portugal Portugal, officially the Portuguese Republic, is a country on the Iberian Peninsula in Southwestern Europe. Featuring Cabo da Roca, the westernmost point in continental Europe, Portugal borders Spain to its north and east, with which it share ...

, his son
(35)

Bile Bile (from Latin ''bilis''), also known as gall, is a yellow-green/misty green fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is primarily composed of water, is pro ...

, King of Galicia, Andalusia, Murcia, Castile, and Portugal, and his son
(36) Galamh (also known as Milesius of Spain), King of Galicia, Andalusia, Murcia, Castile, and Portugal. According to O'Hart's account, Milesius had four sons, Heber, Ir, Heremon, and Amergin, who were involved, with their uncle Ithe, in the invasion of ancient

; Milesius, himself, had died during the planning. Amergin died during the invasion, without issue. It is from the four other invaders — Heber, Ir, Heremon, and Ithe — from whom the Irish are alleged to descend. These, according to O'Hart, are the four lines from which all true Irish descend.

Conn of the Hundred Battles Conn Cétchathach (), or Conn of the Hundred Battles, son of Fedlimid Rechtmar, was a legendary High King of Ireland who is claimed to be the ancestor of the Connachta, and through his descendant Niall Noígiallach, the Uí Néill dynasties, w ...

was a descendant of Erimon, and

Brian Boru Brian Boru (; modern ; 23 April 1014) was the High King of Ireland from 1002 to 1014. He ended the domination of the High King of Ireland, High Kingship of Ireland by the Uí Néill, and is likely responsible for ending Vikings, Viking invasio ...

was descended from both Heber and Conn.

Sources

Irish pedigrees; or, The origin and stem of the Irish nation (1892), by John O'Hart, is available in 2 volumes free on the

Internet Archive The Internet Archive is an American 501(c)(3) organization, non-profit organization founded in 1996 by Brewster Kahle that runs a digital library website, archive.org. It provides free access to collections of digitized media including web ...

. :''Irish pedigrees; or, The origin and stem of the Irish nation (1892), by John O'Hart, - Volume: 1'' :' :''Irish pedigrees; or, The origin and stem of the Irish nation (1892), by John O'Hart, - Volume: 2'' :' Another book by John O'Hart is also available free on the Internet Archive. :''The Irish landed gentry when Cromwell came to Ireland (1887), by John O'Hart;'' :'

External links

Geoghegan family genealogy as compiled by John O'Hart
{{DEFAULTSORT:Ohart, John 1824 births 1902 deaths Celtic studies scholars Irish genealogists 19th-century Irish historians People from County Mayo