City Readers Digital Historic Collections at the New York Society Library

Charles O'Conor, O'Conor Don (Irish: Cathal Ó Conchubhair Donn; 1 January 1710 – 1 July 1791), also known as Charles O'Conor of Belanagare, was an Irish writer and antiquarian who was enormously influential as a protagonist for the preservation of Irish culture and history in the eighteenth century. He combined an encyclopaedic knowledge of Irish manuscripts and Gaelic culture in demolishing many specious theories and suppositions concerning Irish history.

O'Conor was a protagonist for Catholic civil rights in eighteenth century Ireland. He worked relentlessly for the mitigation and repeal of the Penal Laws, and was a co-founder of the first Catholic Committee in 1757, along with his friend Dr. John Curry and Mr. Wyse of Waterford. In 1788 he became a member of the Royal Irish Academy.

His collection of manuscripts and manuscript copies, annotated with his copious notes and comments, made up the first part of the Annals of the Four Masters (originally the property of Fearghal Ó Gadhra) that were collected at the Stowe Library, and at that time many of them were the only copies known to exist.