John Lincoln ‘Jack’ Sweeney was a scholar, critic, art collector, and poet. Born in Brooklyn, New York, he attended university at Georgetown and Cambridge, where he studied with I.A. Richards, and Columbia, where he studied law. In 1942 he was appointed curator of Harvard Library’s Poetry Room (established in 1931 and specialising in twentieth century poetry in English); curator of the Farnsworth Room in 1945; and Subject Specialist in English Literature in 1947. Stratis Haviaras writes in The Harvard Librarian that ‘Though five other curators preceded him, Jack Sweeney is considered the Father of the Poetry Room …’. He oversaw the Poetry Room’s move to the Lamont Library, ‘establishing its philosophy and its role within the library system and the University; and he endowed it with an international reputation’. He also lectured in General Education and English at Harvard. He was the brother of art critic and museum director, James Johnson Sweeney (Museum of Modern Art, New York; Solomon R. Guggenheim Museum, New York; and the Museum of Fine Arts in Houston, amongst others). In 1949 he married Máire MacNeill , a distinguished folklorist and daughter of Eoin MacNeill and Agnes Moore (the novelist Brian Moore was Máire’s first cousin). After his retirement from Harvard, the Sweeneys moved to their house in Corofin, County Clare. 

Máire MacNeill was born in Portmarnock, County Dublin. She grew up in a bi-lingual household, acquiring a deep knowledge of Irish culture: her father was a founding member of the Gaelic League, Professor of Early Irish History at UCD, and Minister for Education, 1922–25, in the first Irish Free State government. Máire was educated at Muckross College, Dublin and UCD, graduating with a BA degree in Celtic Studies in 1925. Initially, she worked as a clerk in the Cumann na nGaedheal office and then as a secretary, journalist and sub-editor until 1935 when she joined the staff of the Irish Folklore Commission where she met the renowned folklorist, Seamus Ó Duilearga. Under his guidance, she worked for several years with a team of people collecting and recording an enormous wealth of folklore. She left the Folklore Commission when she married. Máire and Jack went to live in Boston and she taught in the Department of Celtic Studies at Harvard. Her major publication, The Festival of Lughnasa, was published in 1962. She was awarded a DLitt from the National University in recognition of her work.

The Sweeneys settled in Clare in 1967 and moved to a house beside Lake Inchiquin near Corofin, memorialised in a poem by their friend Richard Eberhart. Máire renewed her ties with the Folklore Commission and continued with her research. Jack died suddenly in 1986 and Máire died the following year. Her generous bequest of a collection of modern art to the National Gallery of Ireland is known as The Máire MacNeill Sweeney Bequest and includes paintings by Picasso, Modigliani, Matisse, Gerard Dillon and Barrie Cooke.

The Sweeney Papers were bequeathed to University College Dublin by Máire Sweeney and were transferred by her sister and executor, Eilis McDowell. The bulk of the collection was transferred on 1 December 1988. It should be noted that letters from certain correspondents to Sweeney are not necessarily situated within this collection. There are indications within the papers, usually consisting of acknowledgements from manuscript librarians and archivists, that Sweeney gave batches of letters from individual correspondents to whatever curatorial institution held the literary papers of that correspondent.