 Francisco Asenjo Barbieri was a key figure in the development of the romantic zarzuela; whilst later composers such as Ruperto Chapí, Federico Chueca and Tomás Bretón brought the genre to its late 19th-century apogee.Leading 20th-century zarzuela composers included Pablo Sorozábal and Federico Moreno Torroba.Fernando Sor, Dionisio Aguado, Francisco Tárrega and Miguel Llobet are known as composers of guitar music.