John O'Hart

Author / Genealogist / Nationalist

John O'Hart
Crossmolina Co. Mayo.
University College, Belfast

Author / Genealogist / Nationalist

This very interesting man devoted his life to antiquarian also genealogical research.  His legacy of  Irish Pedigree  has been perused down through the years.

John O ‘Hart was born in Crossmolina, Co. Mayo during December 1824.  His parents were Nora (daughter of Mary Geraghty & Peter Kilroy of Keenagh, Glenhest) also Shane (John) O ‘Hart.   He had six brothers & four sisters. [i]

John O ‘Hart was born in Crossmolina, County Mayo during 1824. [ii]


He received his education at Crossmolina National School.  Aged ten years old John O ‘Hart was educated at the local classical school. [iii]


John O ‘Hart became an associate at Queen’s University, Belfast.  He participated as a very active member of several scholarly societies. [iv]


John O ‘Hart married Elizabeth Burnett on 25th May 1845 (daughter of Margaret Bourke & Patrick Burnett of Enniscrone)  They had three sons; Patrick Andrew, John Anthony, Francis Joseph, also daughters  Fanny-Mary, Mary- Elizabeth, Margaret, Eliza, Anna also Louisa. [v]


John O ‘Hart joined the Royal Irish Constabulary.  He was stationed within Ballinrobe depot. [vi]

Two years later he resigned from the R. I. C. [vii]

John O ‘Hart spent two years as a police officer. [viii]


John O ‘Hart transferred as assistant clerk to the County Inspectors office in Oughterard, Co. Galway.  He commenced employment with the Commissioners of National Education in Ireland during 1854. [ix]

Ringsend School

He was appointed to the staff of Ringsend School Dublin during 1856. [x]


John O ‘Hart produced his work The Irish Landed Gentry when Cromwell came to Ireland  in 1887 (James Duffy Dublin) that was re-printed with an introduction by Edward Mac Lysaght, the First Chief Herald of Ireland during 1869.  His unique Irish Pedigree; or The Origin and Stem of the Irish Nation was produced during 1876 & 1884 in two volumes. [xi]

John O ‘Hart published When Cromwell Came to Ireland  in 1873: he penned The Last Prince of Tara.  He produced further works during 1875, 1878  & 1881. [xii]

He contributed articles to the  London monthly magazine Hibernia. [xiii]

He continued to re-work subsequent editions thus added greatly to his workload &output.  O ‘Hart produced his eight hundred page 1884  The Irish and Anglo-Irish Gentry.  (H. M. Gill)  [xiv]


To complete his genealogies he studied the writings of Cú Choigcríche Ó Cléirigh, Dubhaltach Mac Fhirbhisigh & O’Farrell.  Also in the Annals of the Four Masters for medieval pedigrees. He used the works of Bernard Burke, John Collins & others to extend his genealogies from the seventeenth century onwards. [xv]


He proved that Queen Victoria was actually descended from the High Kings of Tara in his Irish Pedigree; or The Origin and Stem of the Irish Nation masterpiece!  [xvi]


John O ‘Hart’s demise occurred  at Clontarf in Dublin during 1902 while he was aged seventy-eight years. [xvii]


The National Library has referenced John O ‘Hart with ‘It is clearly the duty of Irishmen to support and encourage native literature.  Here is a countryman of ours who has attained a high rank among contemporary archaeologists by perseverance in face of circumstances after adverse, and it was surely a disgrace and stigma on cultural Irishmen if his works should fail their well – won need of recognition and reward.’   [xviii]


The National Library holds a letter from John O ‘Hart to Chrissie M. Doyle that stated she may have keep his books until the end of the month.  She hoped that they may provide the information for her work. (August 7th  1898)  [xix]

Belfast Linen Hall Library hold the 1876 edition of the ‘rish Pedigree; or The Origin and Stem of the Irish Nation.  [xx]

John O ‘Hart was adopted as the patron of Crossmolina Heritage Society’s Summer School. [xxi]

These publications by John O ‘Hart may be viewed online:

Irish pedigrees; or, The origin and stem of the Irish Nation  1892 volumes 1 & 2.  The Irish landed Gentry when Cromwell came to Ireland 1887. [xxii]

In an article titled John O ‘Hart: Hero and Villain Grehan stated that  for John O ‘Hart as the scope of the work expanded through its various editions O ‘Hart began to incorporate material relating to the non-Gaels: taken from the original sources in the Public Record Office that were destroyed in 1922.  O ‘Hart had an extraordinary appetite for work and appears to have read and absorbed every single Irish pedigree published before the 1870’s.  He was also a passionate nationalist, and this passion shaped and distorted what he wrote.(John Grehan 11th July 2016) [xxiii]





[iv] Ibid

[v] Ibid

[vi]  Ibid




[x] Ibid

[xi] Ibid


[xiii] Ibid


[xv] Ibid




[xix] Ibid


[xxi] Ibid




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