Victor Mahillon and Kathleen Schlesinger, 1911 Encyclopædia Britannica (1911)
“ First, the art of trombone playing was in the 15th century in Germany mostly in the hands of the members of the town bands, whose duties included playing on the watch towers, in churches, at pageants, banquets and festivals, and they, being jealous of their privileges, kept the secrets of their art closely, so that writers, such as the above, although acquainted with the appearance, tone and action of the instrument would have but little opportunity of learning much about the method of producing the sound. ”
