The Sackbut is an ancient musical instrument that is similar to the modern TROMBONE. It was popular in Europe during the Middle Ages and Renaissance periods, and is considered to be the predecessor of the TROMBONE. The Sackbut has a slide mechanism that allows the player to change the pitch of the notes they are playing. It is made of brass and has a bell-shaped mouthpiece. The sound of the Sackbut is mellow and warm, and it is often used in classical and jazz music.