Georges C. Mager (1885–1950) was a French musician, and principal trumpet with the Boston Symphony Orchestra from 1919 until his death in 1950.
After serving in the French army during the war he came to America as flugelhorn soloist with the Garde Republicaine Band and was engaged to play in the Boston Symphony, first as a violist, since there was no vacancy for trumpet, sharing a stand with Arthur Fiedler.
He was an advocate of use of the C trumpet as an orchestral instrument and had great influence on its development and acceptance in America, working most notably with Vincent Bach.
[1] He also was the first trumpeter in America to play Bach's Brandenburg Concerto in the original high tessitura.
Mager also made important contributions to the trumpet literature through several editions of French solo works, including Guillaume Balay's Petite Piece Concertante, Henri Dallier's Fete Joyeuse, and Georges Hue's Solo De Concert.