Some bands, like Osanna, Area, Perigeo and Arti & Mestieri (Arti e Mestieri), fused progressive rock with jazz, fusion and world music. Il Balletto Di Bronzo's "YS" is one of the most debated Italian prog-rock albums; Some calling it trash and others extolling it as one of the greatest progressive albums ever made. Another important album of the time was "Arbeit macht frei" by Area. They merged agit-prop lyrics, jazz-rock jamming, raw electronics, middle-eastern scales and psychotic warbling, creating an original mixture of different music styles. Area were fronted by Demetrio Stratos, one of the most original singers of his age, who recorded experimental albums entirely devoted to the human voice such as "Cantare la Voce". The same period, the early 1970s, also saw the rise of Italian singers and songwriters like Lucio Battisti, Fabrizio De André, Franco Battiato, Paolo Conte and Francesco Guccini.