Papers, [1822]-1953, of John Rhŷs, comprising a considerable group of letters to him, 1860-1915, including those from fellow researchers, friends and family; material, 1864-1919, relating to his published works, including manuscript drafts of books, articles, and addresses; and research notes, 1836-[1920x1945]. There are also personal and professional papers, [1822]-1953, belonging to, and accumulated by, John Rhŷs; and papers, 1862-[1947], relating to various family members, among them a substantial body of material accumulated by Myvanwy Rhys for a proposed biography of her father.