When and why did the C trumpet take over from the Bb in orchestra's. Who was most responsible for this??? Thanks Chris We have the French to thank for that. Georges Mager, Marcel LaFosse with Boston. Mager was a famous orchestral trumpet player (joining the Boston Symphony in 1918, LaFosse in 1926, Roger Voisin 1927) and had as one of his better students one Adolph Herseth. Bud studied with LaFosse and Mager at the New England Conservatory on the GI bill after WW II. Mager played in Boston for a good thirty years under Koussevitsky and Monteaux. These great players brought the French C with them, brought that wonderful sound to the Boston Symphony. Heim (1906-1920), Bach (1914-1915), Kloepfel (1898-1927), Shuebruk (1880's) were Bflat players. Vacchiano, then Herseth gave the C to the later part of the 20th Century. Mager and LaFosse and Voisin to the first half. Before Vacchiano and Herseth there were three big names in Orchestral Trumpet playing. Mager, Saul Caston and Harry Glantz. Caston a brilliant soloistic player, Glantz the solid first trumpet player. The C trumpet seems to be well entrenched in todays Orchestra.