Correspondence, together with some tracts, petitions, press releases and cuttings, and administrative and financial documents, together with some minutes of Annual General Meetings and copies of minutes of branch meetings, 1962-1999. Correspondents include Clive Betts, Zonia Bowen, Noëlle Davies, Noel Dempsey, Per Denez, Peter Berresford Ellis, Gwynfor Evans, Julian Cayo Evans, Garret FitzGerald, Yann Fouere, Nick Griffin, Neven Henaff, Alan Heusaff, John Jenkins, John Legonna, Tomas Ó Canainn, Padraig Ó Snodaigh, Meic Stephens, Alan Stivell, Dafydd Elis Thomas, Dafydd Wigley and Jac L. Williams. The matters discussed include the aims of the League, its policies and campaigns, the Celtic countries and cultures, linguistic minorities, political movements and ideas, and the compilation, publication and distribution of Carn. There are also articles submitted for Carn, together with notes, as well as letters and petitions to governments and international bodies. In addition, there are copies, drafts and notes of letters written by Heusaff and Moffatt, and letters and other documents forwarded by branch secretaries relating to matters of particular concern.