Septeto Nacional (National Septet), or the Septeto Nacional de Ignacio PiÃ±eiro, is a group credited with expanding the Son (music) musical style before Arsenio RodrÃguez. It added the trumpet to percussion, vocals, and strings. The group started as a sextet in 1927 in Central Havana. In 1929 it played at the World Exposition in Sevilla, and in 1933, it was invited to the "Century of Progress" World Exposition in Chicago. In the same year, LÃ¡zaro Herrera took over the group when Ignacio PiÃ±eiro left it for financial reasons - despite their success the musicians earned very little. The group disbanded in 1937 but resumed playing for a recording session in 1940 and a television appearance in 1954. After the Cuban revolution of 1959, the group played again and is still playing. Its CD Poetas del Son was nominated for a grammy in 2004.