Classical guitar may vary, but the typical shape is either "modern classical guitar" or that "historic classical guitar" similar to the early romantic guitars of France and Italy. Classical guitar strings once made of gut are now made of such polymers as nylon, with fine wire wound about the acoustically lower (bass side) strings. A guitar family tree may be identified. The flamenco guitar derives from the modern classical, but has differences in material, construction and sound. Today's "modern classical guitar" was established by the late designs of the 19th-century Spanish luthier, Antonio Torres Jurado. The classical guitar has a long history
Classical guitar overall interpretation. Thus over recent decades we have become accustomed to specialist artists with expertise in the art of vihuela (a 16th-century type of guitar popular in Spain), lute, Baroque guitar, 19th-century guitar, etc. Different types of guitars have different sound aesthetics, e.g. different colour-spectrum characteristics (the way the sound energy is spread in the fundamental frequency and the overtones), different response, etc. These differences are due to differences in construction; for example modern classical guitars usually use a different bracing (fan-bracing) from that used in earlier guitars (they had ladder-bracing); and a different voicing was used by the luthier.