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 type of repertoire is usually performed by guitarists who have particularly chosen to focus on the avant-garde in their performances. Within the contemporary music scene itself, there are also works which are generally regarded as extreme. These include works such as Brian Ferneyhough's "Kurze Schatten II", Sven-David Sandström's "away from" and Rolf Riehm's "Toccata Orpheus", etc. which are notorious for their extreme difficulty. There are also a variety of databases documenting modern guitar works such as Sheer Pluck and others. The evolution of the classical guitar and its repertoire spans more than four centuries. It has a history that was