Denis Rolleston Gwynn
He was the second son of Stephen Gwynn, writer and scholar. He was educated at St. Enda's School Rathfarnham, Clongowes Wood College and at University College Dublin where he graduated B.A. (1914), M.A. (1915) and D.Litt (1932).
Gwynn served from 1916-17 on the Western Front in France during World War I (as did his father), but was invalided home when he worked at the British Ministry of Information. He began work as a journalist in London and in Dublin where he was editor of The Dublin Review. During World War II he farmed in Hampshire.
He returned to Ireland and was appointed as research professor of Modern Irish History at University College Cork in 1948, a position he held until his retirement in 1962. He acted as editor of the Cork University Press (1954–1962) and wrote a regular column called "Now and Then" in the Cork Examiner. As well as being a writer of history he was a writer of biography.
The novelist Jessie Victor Rickard lived the latter years of her life, until her death in 1963, in his Mentenotte home in Cork. Jessie Rickard was a close friend of his wife's, a daughter of Lady Hazel Lavery by her first marriage.
- The Catholic Reaction in France(1924)
- The Irish Free State, 1922-1927 (1928)
- A Hundred Years of Catholic Emancipation (1929)
- Daniel O’Connell, the Irish Liberator (1929)
- The Life and death of Roger Casement (1930)
- John Keogh: the pioneer of Catholic Emancipation (1930) (1934)
- Daniel O’Connell and Ellen Courtney (1930)
- The Life of John Redmond (1932)
- De Valera (1933)
- The O'Gorman Mahon (1934)
- The Vatican and the War in Europe (1940)
- William Smith O'Brien (1946)
- Young Ireland and 1848 (1949)
- Cardinal Wiseman (1950)
- The history of Partition (1950)
- A Dictionary of Irish History since 1800, D. J. Hickey & J. E. Doherty, Gill & MacMillan (1980)
- A Biographical Dictionary of Cork, Tim Cadogan & Jeremiah Falvey (2006), p. 117