Breese served in the Volunteers and during the First World War, he fought in the European theatre, reaching the rank of Major.
The former MP for Eifion, Ellis William Davies was a supporter of H H Asquith and strongly opposed to Lloyd George.
He tried to manoeuvre his succession to the new Caernarvonshire seat by quickly setting up a combined Arfon and Eifion Liberal Association and packing it with his own supporters to secure the nomination.
Many of the local Liberal Clubs refused to acknowledge Ellis' nomination by this route however and chose their own delegates who convened a new adoption process.
Breese won the contest and went on to face both men in the general election itself, Jones standing as an Independent Labour candidate and Ellis Davies as a Liberal but in support of the Asquithian party.
Breese died from heart failure while grouse shooting on Arenig Mountain near Bala on 15 August 1932, aged 65 years.
The collection consists of his own papers and others acquired by him covering the period 1771–1932, including rentals and accounts for the Brithdir area, Merionethshire, 1802–1848; papers relating to the War Agricultural Committee, 1916; materials relating to Kalendars of Gwynedd, 1872–1873, which was written by his father Edward Breese; papers relating to Crown and Common lands in Wales, 1909–1920; correspondence and notes addressed to Charles E. Breese in his capacity as MP for Caernarvonshire, and correspondence submitted to him for reference, 1912–1923; miscellaneous letters, mostly addressed to Charles E. Breese, 1887–1932; correspondence from G. Rutter Fletcher to Robert Isaac Jones ('Alltud Eifion'), 1835–1905, relating to the pedigree of the Rutter family, with a copy of the pedigree; newspaper cuttings, containing articles of Welsh interest, such as Disestablishment of the Church in Wales, Crown lands in Wales etc., 1909–1920; and miscellaneous papers, 1858–1932; together with maps and prints, etc., 1771–1932.