The flugelhorn (also spelle fluegelhorn 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 stems from the keyed bugle by Michael Saurle (father), Munich 1832 (Royal Bavarian privilege for a "chromatic Flügelhorn" 1832), thus predating Adolphe Sax's innovative work.