Ruaidhrí Ó Flaithbheartaigh

Roderic O Flaherty (Irish name Ruaidhrí Ó Flaithbheartaigh, Ruairí Ó Flaitheartaigh) (1629 – 1718 or 1716), was an Irish historian. He was born in Co Galway and inherited Maigh Cuilinn (Moycullen) Castle and estate.

O'Flaherty was the last de jure Lord of Iar Connacht, and the last recognized chief of the O'Flaherty clan. He lost the greater part of his ancestral estates to Cromwellian confiscations in the 1650s. The remainder was stolen through deception, by his son's father-in-law, Richard Nimble Dick Martin of Ross. Died in poverty at Park, near Bearna.

Uniquely among the O Flaithbheartigh family up to that time, Ruaidhri became a highly regarded historian and collector of Irish manuscripts. His friends and associates included his teacher Dubhaltach MacFhirbhisigh; Daibhidh Ó Duibhgheannáin; Dr. John Lynch; Edward Lluyd; Samuel Moleneaux and his father William. His published works included Ogyia and Iar Connacht.

He is perhaps most often associated with his elaborate history of Ireland, Ogygia, published in 1685 as Ogygia: seu Rerum Hibernicarum Chronologia & etc., in 1793 translated into English by Rev. James Hely, as
 * "Ogygia, or a Chronological account of Irish Events (collected from Very Ancient Documents faithfully compared with each other & supported by the Genealogical & Chronological Aid of the Sacred and Profane Writings of the Globe"

Ogygia is the island of Calypso, used by O'Flaherty as an allegory for Ireland. Drawing from numerous ancient documents, Ogygia traces Irish history back to the ages of mythology and legend, before the time of Christ. The book credits Milesius as the progenitor of the Goidelic people. O'Flaherty had included in his history what purported to be an essay on the understanding of the ancient Ogham alphabet. Based on the 1390 Auraicept na n-Éces, he stated that each letter was named after a tree, a concept widely accepted in 17th century Ireland. Ogygia was immediately criticised for its scholarship by Sir George Mackenzie of Rosehaugh (1636-91), Dean of Faculty (1682) at Aberdeen. The arguments about O'Flaherty's continued well into the 18th century, culminating in the 1775 The Ogygia Vindicated by the historian Charles O'Conor, in which he adds explanatory footnotes to the original work.

He was survived by his daughters, and a son, Micheal Ó Flaithbheartaigh.