This study examines what makes a keyed brass instrument, early keyed brass instruments, and keyed brass instruments of today. Focuses on the Cornett, the Serpent, the Basshorn and Russian Bassoon, the Ophicleide, the Horn, the Keyed Trumpet, and the Keyed Bugle.

The purpose of this thesis is to bring to light some of the music written for, or especially adaptable to, brass ensembles before the close of the eighteenth century. This study must concern itself with the music which has been preserved and is available, and with such music as can be played on modern instruments. It must be stated that some of the music mentioned herein was not written specifically for brass instruments, but the style and general character of the music make it adaptable for a brass instrumentation.

The significance of the application of valves to brass instruments will be better understood by a brief discussion of conditions immediately preceding this innovation.