Overview
Denis O'Conor, O'Conor Don (; 1794–1847) of Clonalis, County Roscommon, was an Irish nobleman, and Member of Parliament (MP) in the British House of Commons.
Early life and family
He was born in May 1794 to Owen O'Conor, O'Conor Don and his wife Jane Moore daughter of Edward Moore of Mount Browne, County Dublin and Jane Reynolds. Denis was the eldest of four children. He had one brother Edward who became an agent for their father and then to Denis, and two sister Jane and Catherine. He was brought up in Belanagare in County Roscommon until his father moved the family to Clonalis on the death of his fourth cousin once removed, Alexander O'Conor, O'Conor Don in 1820 whom his father inherited the title of O'Conor Don.
The O'Conors were prominent Catholic gentry who had been the traditional Kings of Connacht and counted among their ancestors two twelfth-century High-Kings of Ireland, Tairrdelbach Mor Ua Conchobair and Ruaidrí Ua Conchobair who was the last high king of Ireland.
On his father's side, he was a nephew of Rev. Charles O'Conor and Matthew O'Conor. His father's first cousin was Thomas O'Conor and therefore Denis was a second cousin of Thomas's son Charles O'Conor of New York. His great-grandfather was the eminent antiquarian, writer and protagonist for catholic civil rights during the penal laws, Charles O'Conor of Belanagare.
His maternal grandfather was a wealthy Catholic brewer in Dublin who was descended from Lewis O'More youngest brother of Rory O'More. His maternal grandmother was a daughter of Thomas Reynolds of Rathfarnham and Dundrum Castle. Thomas was a successful Silk manufacturer who descended from a cadet branch of Mac Raghnaill chiefs of Lough Scur in County Leitrim. Through this connection Denis's Mother was a first cousin of Thomas Reynolds.
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