Other Armenian diasporans that rose to fame in classical or international music circles are world-renowned French-Armenian singer and composer Charles Aznavour, pianist Sahan Arzruni, prominent opera sopranos such as Hasmik Papian and more recently Isabel Bayrakdarian and Anna Kasyan. Certain Armenians settled to sing non-Armenian tunes such as the heavy metal band System of a Down (which nonetheless often incorporates traditional Armenian instrumentals and styling into their songs) or pop star Cher. In the Armenian diaspora, Armenian revolutionary songs are popular with the youth. These songs encourage Armenian patriotism and are generally about Armenian history and national heroes.