The flugelhorn (also spelled fluegelhorn, flugel horn or flügelhorn; is a brass instrument resembling a trumpet but with a wider, conical bore. Some consider it to be a member of the saxhorn family developed by Adolphe Sax (who also developed the saxophone); however, other historians assert that it derives from the keyed bugle designed by Michael Saurle (father), Munich 1832 (Royal Bavarian privilege for a "chromatic Flügelhorn. Thus predating Adolphe Sax's innovative work.