Charles O’Conor, DD (Belanagar 1764 – Belanagar 1828), namesake and grandson of Charles O’Conor of Belanagar, was born on the family estate and, as a second son, sent to train for the priesthood. He studied at the Irish College in Rome, where he was ordained and graduated as doctor of divinity. While in Italy, he (like John Lanigan) was inspired by the Enlightenment Catholicism of Muratori and also by Muratori’s historical scholarship and source-criticism. He and Lanigan were both members of the Academy of Cortona, that academy being a centre for archeological interest in Etruscan culture and the town being a Jansenist centre. Charges of Jansenism (in reality probably a catch-all term for Enlightenment rationalism and reservations about papal prerogative) were later to pursue O’Conor, who returned from Italy in 1791 but found it difficult to settle back in rural Ireland.

In 1799 he accepted an offer from the marquess of Buckingham to become his private librarian and house chaplain to his (Catholic) wife. When entering into Buckingham’s employ, O’Conor took with him some of the most important items of the family’s collection of Gaelic MSS, much to the chagrin of his relatives. These were made part of Buckingham’s private library at his Stowe estate and would decades later, as “Stowe MSS”, be acquired by the Royal Irish Academy – exemplifying the typical trajectory of such material: from privately-owned working property to collectables for wealthy amateurs to public archival repositories.

At Stowe, O’Conor used this material to compile Muratori-style regests of ancient materials in Irish history. The raw outline of what might later become a Gaelic literary history, this work appeared as Rerum Hibernicarum scriptores veteres, sumptuously printed at Buckingham’s expense in 4 volumes between 1814 and 1828. The text was later strenuously criticized by a new generation of philologists, but together with Edward O’Reilly’s similar literary-historical outline of 1820, it marks the first annalistic prelude to Gaelic literary history-writing – as distinct from antiquarianism.

O’Conor’s rebarbative personality often got him into conflict with his familial or ecclesiastical seniors; eventually, his mind became unbalanced. He left the Buckingham household in 1827 and died the next year on the O’Conor family estate.