The natural horn or hunting horn is a brass instrument with mouthpiece; his long tube has neither holes nor piston valves (which are, instead, present in other brass instruments). Different notes are obtained by producing harmonic. These two items are the most precious items in the entire section of wind instruments at the Sforza Castle. To date they are the oldest pair of orchestral horns to be preserved in the world. The mark on the bell presents the name Michael Leichamschneider, the most representative manufacturer of horns who worked in Vienna in the early 18th century. He and his brother Johann (1679- after 1725) were most likely the first to create this type of instruments especially for orchestral use.