Johann Kaspar Mertz brought the classical guitar into the lyrical and virtuosic world of Romantic concert music. His pieces often treat the instrument like a miniature piano or songful salon voice, with tremolo, arpeggio, and dramatic contrast. Bardenklänge, Elegie, and his opera fantasies place him alongside the 19th-century guitar tradition that followed Sor, Giuliani, and the Viennese salon.