The Celtic League was started at the 1961 National Eisteddfod of Wales, which was held at Rhosllannerchrugog near Wrexham in northeast Wales. Two of the founding members were Gwynfor Evans and J. E. Jones, who were respectively president and secretary-general of the Welsh nationalist political party Plaid Cymru at the time. Interest was expressed by Scottish parties, and also by Breton nationalists.