There is 1 Ermenegildo Magazzari (born 1767) original bassoon in the Hichwa-Rachor database. He flourished in fl. Bologna a1792-p1813. He seems to have been a successful woodwind instrument maker; the firm continued into the second half of the 19th century.
Ermenegildo Magazzari Bassoon Literature
Waterhouse, William. The New Langwill Index. London: Tony Bingham, 1993.