Seventeen letters, mostly in Welsh, to Saunders Lewis from Lascelles Abercrombie (2) 1926 and n.d., W. R. P. George (1) 1978, David Howell ('Llawdden') (1) 1901, R. S. Thomas (1) ?1970s, and Lewis Valentine (12) 1972-83; together with three letters, 1936-7, to Margaret Lewis from P. Mansell Jones, J. E. Jones, and Siân Williams, written during Saunders Lewis's imprisonment.

Ninety-four letters, 1919-1984, in Welsh and English, to Saunders Lewis from various correspondents, together with a few draft letters from Saunders Lewis and four letters to Margaret Lewis, written during her husband's imprisonment in 1937. Subjects discussed include Welsh nationalism, the award of DLitt honoris causa to Saunders Lewis, the Welsh Burial Grounds issue, 1928, and literary topics; enclosures include a copy of a draft constitution and articles of agreement, 1934, relating to self-government for Wales (ff. 161-95). Among the main correspondents are Edward Glyn Jones (13) 1919-28, Robert Williams Parry (14) 1927-44, John Arthur Price (5) 1928, E. Prosser Rhys (3) 1927-9, D. J. Williams, Fishguard (7) 1948-67, and Griffith John Williams (3) 1935-56.