Her lineage as a daughter (possibly pre-marital) of Rory O'Donnell, 1st Earl of Tyrconnell, and his wife Lady Bridget FitzGerald, was repeatedly cited in various peerage directories, such as Lodge's (1827, and re-issued in 1907),[3] Foster's (1881),[4] Cokayne's (1926),[5] and Burke's (1980).[6]
However, Elizabeth is clearly and more authoritatively identified as the second daughter of Henry FitzGerald, 12th Earl of Kildare and Lady Frances Howard, and was, therefore, the sister of Rory's wife, Lady Bridget née FitzGerald, properly recorded in the histories of the FitzGeralds of Kildare, based on their own family archives in Carton House and Kilkea Castle, and on no better authority than Charles FitzGerald, 4th Duke of Leinster himself, writing at the time as Marquis of Kildare (and before the later erroneous authors), and who confirmed that Elizabeth married Luke Plunket, 1st Earl of Fingall in 1608.[7] Later sources confirmed this, i.e. that this Elizabeth was a FitzGerald, the Countess Lady Bridget's sister, and not her daughter.[8] Elizabeth is said to have died in London in 1611 during an outbreak of the plague only three years after her marriage.[9]
Lord Killeen, later Earl of Fingall, was also married on three other occasions. He had married in 1628 Eleanor Bagenal, who died leaving no children. His son by a later marriage to Susanna Brabazon, Christopher Plunket, 2nd Earl of Fingall, married Mabel Barnewall, niece of Elizabeth through her sister, Bridget, whose second husband was Nicholas Barnewall, 1st Viscount Kingsland, from whom she had more children. Another niece, Mary Barnewall married Nicholas Preston, 6th Viscount Gormanston. Lucas Plunket's last wife was Margaret St. Lawrence, daughter of Nicholas St Lawrence, 9th Baron Howth. Plunket died on 29 March 1637; Margaret died the following November.
^Meehan, C. P. The Fate and Fortunes of the Earls of Tyrone and Tyrconnel (1870). Meehan believed of the Countess of Tyrconnell (Bridget) that "by the earl of Tyrconnel she had one son, Hugh, who succeeded to his father's title, and two daughters, Eliza and Mary" (footnote, page 246)
^Carty, Mary Rose. History of Killeen Castle, published by Carty/Lynch, Dunsany, County Meath, Ireland, April 1991 (ISBN0-9517382-0-8) – page 18 refers to Elizabeth O'Donnell as 1st Countess of Fingall (Fingal). She was said to be a daughter of Rory O'Donnell, 1st Earl of Tyrconnell
^Lodge, Edmond, Esq., Late Norroy King-of-Arms. Lodge's Peerage, Baronetage, and Knightage for the British Empire for 1907, 76th edition, published by Kelly's Directories Ltd., High Holborn, London (1st edition was published by College of Arms, 1827)
^Foster, Joseph. The Peerage, Baronetage, and Knightage of the British Empire for 1881, published by Nichols & Sons, Westminster, 1881
^Cockayne, George Edward. The Complete Peerage of England, Scotland, Ireland, Great Britain, and the United Kingdom, extant, extinct or dormant, Volume V, published by The St. Catherine Press, London, 1926
^Burke's Peerage and Baronetage, 105th edition, 4th impression, published by Burke's Peerage (Genealogical Books), Ltd, 1980 ISBN0-85011-034-3
^FitzGerald, Charles William (Marquis of Kildare and later 4th Duke of Leinster). The Earls of Kildare and their Ancestors: from 1057 to 1773, 4th edition, published by Hodges, Smith & Co., Dublin, 1864 (pp. 235–236). He made the same mistake himself, i.e. that Elizabeth was a daughter rather than a sister of Bridget, in the second edition of 1858 (page 226), but corrected this in his fourth edition in 1864
^Cockayne, George Edward. The Complete Peerage of England, Scotland, Ireland, Great Britain, and the United Kingdom, extant, extinct or dormant, Volume V, published by The St. Catherine Press, London, 1926 (page 385). To have been married in 1608, she cannot have been the marriageable daughter of Bridget who was herself only about 19 years old at that time, but rather her sister
Bagwell, Richard (1895). "O'Donnell, Rory" . In Lee, Sidney (ed.). Dictionary of National Biography. Vol. 41. London: Smith, Elder & Co. pp. 444–447. "Lady Tyrone [(Bridget)] had a daughter, Mary Stuart. Another daughter, Elizabeth, is often given to her; but on a comparison of dates it seems doubtful whether the lady in question was not her sister, who married Luke, first earl of Fingal (pedigree in Earls of Kildare, Addenda)."
Silke, John J. (May 2006) [2004]. "O'Donnell, Rory , styled first earl of Tyrconnell (1574/5–1608)". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/20559. (Subscription or UK public library membership required.) "Hugh Albert O'Donnell, born [to Rory and Brigid] about October 1606, was the only son of this marriage, Mary Stuart O'Donnell being born about a year later. Some authorities give an eldest child, Elizabeth, probably illegitimate, who became first wife of Luke Plunkett, first earl of Fingall."
