O'Flaherty, Roderick (Ó Flaithbheartaigh, Ruaidhrí) (1629–1718), historiographer, was born in late 1629 at Moycullen, Co. Galway, to Hugh O'Flaherty, proprietor of the castle and manor of Moycullen, and his wife Elizabeth, daughter of Alderman Martin Darcy of Galway city and a relative of Patrick Darcy (qv). Hugh O'Flaherty died 20 October 1631 when his only son was not quite two years of age. Roderick O'Flaherty became a ward of the crown and his mother married John Bermingham, son of Richard, 16th baron of Athenry. The details of O'Flaherty's education are not known for certain, but the fact that he was acquainted with John Lynch (qv) before the latter left Ireland in 1652, together with his excellent command of English and Latin, is consistent with the view that he studied at Lynch's school in Galway during the 1640s. In 1652 he married a daughter of Col. Morrough ‘na dTuagh’ O'Flaherty, a distant relative. The bulk of his father's estate was confiscated in the Cromwellian land settlement, although the commissioners at Loughrea assigned him a small property in view of his minority at the time of the 1641 rebellion. Heavy impositions by the new régime and the economic disruption resulting from a decade of war ensured that O'Flaherty benefited little from this judgement and he lived in straitened circumstances at Park, between Furbogh and Spiddal, during the interregnum. In April 1677 he was granted 500 acres under the restoration land settlement, but by then he was heavily indebted and continued to live on and to farm his holding at Park.
O'Flaherty's most celebrated work, a chronology of Irish history in Latin entitled Ogygia: seu, rerum Hibernicarum chronologia, was undertaken at the suggestion of John Lynch, who also assisted in so far as he could from his place of exile in France. A letter from O'Flaherty to Lynch that was included in the published book indicates that it was essentially complete by 1665, although it did not appear in print until 1685, when it was published in London with a dedication to James, duke of York – shortly to become James II (qv) – whose Irish ancestry was emphasised. In compiling the chronology O'Flaherty made use of an impressive array of primary sources including the Annals of Tigernach, Chronicon Scotorum, Annals of Clonmacnoise, Book of Leinster, Book of Uí Maine, Book of Lecan, and Annála ríoghachta Éireann (Annals of the Four Masters). He obtained access to some of these sources through his friendship with the antiquary Dubhaltach Mac Firbhisigh (qv), whose help he acknowledged. O'Flaherty also displayed a wide knowledge of foreign history when synchronising events in Ireland with those in other countries, but his treatment of mythological, literary, and biblical sources was unduly credulous. Thus he began his chronology of Irish history with the arrival of the first inhabitant, Partholan, in Co. Kerry on Wed. 14 May, 312 years after the flood and 1,969 years after the creation. For the historical period, however, O'Flaherty's painstaking calculations represented an important advance: for example, he gave the correct date of the battle of Clontarf (23 April 1014) although Geoffrey Keating (qv) and Micheál Ó Cléirigh (qv) had placed it in 1034 and 1015 respectively.
Publication of Ogygia was facilitated by William Molyneux (qv), with whom O'Flaherty became acquainted when he was commissioned by him to write an account of the topography, flora, fauna, and customs of west Galway for a projected atlas. The atlas did not appear but Molyneux recognised the value of O'Flaherty's contribution and preserved it in his papers; it was eventually edited by James Hardiman (qv) and published under the title A chorographical description of West or h-Iar Connaught in 1846. This initial contact laid the basis for a scholarly friendship in which O'Flaherty advised Molyneux on Irish antiquities and the latter secured some financial assistance for the antiquary.
O'Flaherty had openly expressed his loyalty to the reigning Stuart dynasty in Ogygia, tracing its descent from the Irish kings of Dál Riata and portraying the accession of James I in 1603 as the restoration of a native monarchy after a hiatus of 405 years that began with the death of the last high king, Ruaidrí Ua Conchobair (qv). O'Flaherty's essentially accurate representation of the kingdom of Scotland as the outgrowth of a sixth-century Irish colony conflicted with a cherished pseudo-historical narrative elaborated by such Scottish authors as John of Fordun and Hector Boece that traced the history of the Scottish monarchy back to the fourth century BC. O'Flaherty's views on the issue were attacked by Sir George Mackenzie, lord advocate of Scotland, in a pamphlet entitled The antiquity of the royal line of Scotland and the Irishman responded to his critic in The Ogygia vindicated, a book in English which sought to show ‘the antient Irish to have been the genuine primogenial Scots’ (p. 1). The body of this text must have been written shortly after Mackenzie's pamphlet appeared, as O'Flaherty stated in the preface that it had already remained in manuscript for twenty-eight years. In the event, it did not appear in print until 1775 when Charles O'Conor (qv) saw an edition through the press as part of an effort to expose the Ossianic forgeries of James MacPherson (1736–96).
O'Flaherty again proclaimed his loyalty to the Stuart dynasty by composing a poem in Latin to celebrate the birth in 1688 of James, prince of Wales, and this was published in Dublin under the title Serenissimi Walliæ principis, Magnæ Britanniæ et Hiberniæ, cum appendicibu dominiis haeredis conspicui genethliacon. The Williamite war further weakened his financial position and, fearing further confiscations in the aftermath of the revolution, he apparently transferred some of his property for safe-keeping to a former Jacobite officer, Richard Martin, who enjoyed the protection of the articles of Galway. His final years were spent in straitened circumstances. A letter that he wrote to William Molyneux in January 1697 was addressed from Galway gaol, although it is unclear if he was confined there at the time. Comments by Edward Lhuyd (qv), who visited him about 1700, and by William Molyneux's son Samuel, who visited him in 1709, indicate that he was impoverished and had been forced to sell almost all of his books and manuscripts.
O'Flaherty's only son, Michael, was an officer in the Austrian service and succeeded in recovering some of his father's lands from Richard Martin after a protracted lawsuit. O'Flaherty also had at least one daughter, who married Edward Tyrell (qv), a member of the established church and a notorious priest-catcher who was executed for bigamy in 1713. James Hardiman stated that O'Flaherty died 8 April 1718. According to tradition he was buried on his holding at Park, as his son believed this would strengthen his title to the property.