The trumpet is one of the oldest brass instruments, and the one with the higher register among them. They have been used as musical instruments at least since the 15th century, and they also have served strictly non artistic purposes such as signaling the arrival of a king or high officer. The instrument evolved throughout the years, with the last important modification being the addition of valves, which happened almost two hundred years ago. The most common trumpet nowadays is the Bb trumpet, a transposing instruments with three valves. It is a standard orchestral instrument, and also used in jazz, rock, pop, and folkloric music.