Cors solo, a French invention, are horns built specifically for the use of soloists. They not only are extremely carefully crafted but also have a slightly narrower bore than regular orchestral French horns. Only a few shops, most of them in Lyon and Paris, were able to build excellent, easy-speaking cors solo with refined workmanship and balanced sound qualities. This cor solo, dated 1829, is the earliest known instrument made by Dubois & Couturier, a firm that flourished in Lyon in the 1830s. The style of the ferrules and stays between the sections of tubing was very modern for the time and became generally accepted only in the 1850s. Because in the early nineteenth century literally all solo literature for cors solo was composed in the keys of G, F, E, and E-flat, the horns were built with exchangeable loops just for those keys.
This instrument has been used very little. It survives in a form-fitting case covered with leather and lined with chamois. A metal plaque on the case's lid bears the monogram, MG, of the musician who owned the instrument.