The Cwrtmawr Manuscripts are a collection of 1,549 volumes of medieval Welsh documents, mainly texts of Welsh literature, collected by John Humphreys Davies, who lived at Cwrtmawr near Llangeitho in Ceredigion and was principal of the University College of Wales, Aberystwyth from 1919-1926. The manuscripts are now kept in the National Library of Wales.
John Humphreys Davies was a bibliographer whose interest in Welsh literature and culture manifested in the collection of manuscripts that he acquired from many different sources over a period of many years. In his Report on Manuscripts in the Welsh Language for the Historical Manuscripts Commission, J. Gwenogvryn Evans gave credit to Davies for rediscovering manuscripts that were considered to be lost and drawing attention to other, previously unknown manuscripts. Evans also stated that despite being too modern to fall within the scope of his Report, the collection of Welsh Ballads in Cwrtmawr manuscripts are "very valuable". In 1925, Davies transferred the fifty manuscripts that Evans had catalogued (i.e. Cwrtmawr 1-50) to the National Library of Wales. He bequeathed the entire collection to the National Library when he died on 10 August 1926.
A greater proportion of the Cwrtmawr manuscripts are from the eighteenth and nineteenth centuries but there is, nonetheless, also a reasonable number of sixteenth and seventeenth century manuscripts. The collection is predominantly of Welsh literary interest and contains a variety of different material including: religious works such as sermons and hymns, volumes of annotated press cuttings, holograph letters, diaries and journals, account books, pedigrees, commonplace books, recipes, dictionaries, music, and notes on philology and bibliography.
John Humphreys Davies acquired the Cwrtmawr manuscripts over a long period of time and from many sources. The largest group is the manuscripts that Davies acquired from John Jones (Myrddin Fardd) on various occasions. Other substantial groups are from the collections of: the Richards family, Revs. Peter Bailey Williams and St George Armstrong Williams, William John Roberts (Gwilym Cowlyd), and Rev. Daniel Silvan Evans.