An octet can be a group of eight players, or a composition created for such a group. Before the 19th century, writing for eight performers was common when it came to serenades and divertimenti. However, the word 'octet' first appeared as a title for a composition with Prince Louis Ferdinand's Octet Op. 12. (for flute, clarinet, 2 horns, 2 violins, and 2 cellos). Octets can be written for string ensembles (such as Mendelssohn's Op. 20), double string quartets, only-cello octets, wind octets, or hybrid wind/string ensembles.