Which instrument originally did not have valves and was used by military?

The instrument that originally did not have valves and was commonly used by military bands is the bugle. The bugle is a brass instrument that produces sound through the player's lips vibrating against the mouthpiece and relies on the player's ability to change pitch by altering their embouchure and using different harmonic series. Its simplicity and portability made it an essential tool for military signaling and communication.