Papers, 1931-1993, accumulated by Delwyn Phillips, including minutes, accounts and correspondence of Undeb y Brythoniaid, 1931-1974; minutes and correspondence, 1931-1976, of Plaid Cymru Midlands Branch; minutes and correspondence, 1947-1979, of Pwyllgor Undebol Cymry Birmingham a'r Cylch; and correspondence and papers, 1956-1992, of the Celtic Congress.