Roderick O'Flaherty (born 1629) was an Irish aristocrat, historian and antiquarian. Here his letters are published with annotation and biographical detail by Richard Sharpe FBA, Professor of Diplomatic at Oxford and Fellow of Wadham College. O'Flaherty's life was active both intellectually and politically: he lost his estate under Cromwell and was further dispossessed when King William began to control Galway in 1696. Previously unseen correspondence is uncovered, including O'Flaherty's exchanges with the Welsh lexicographer Edward Lhwyd (1660-1709), and the Irish philosopher William Molyneux and his son Samuel. Letters from late in his life show the scholar's continued involvement with the world of learning and provide a remarkable insight into scholarly engagement across cultures and countries. O'Flaherty's 'Iar Connaught' (1684) is included, a lively description of Moycullen in County Galway, where the family manor was held. This epistolary collection stands as a unique portrait of a Gaelic lord, Latin author, historian and antiquarian and a record of the world he moved in.