合奏協奏曲
In 1971 they released the album which was to become their trademark: "Concerto grosso per i New Trolls". The album was a fantastic example of early symphonic rock experimentation, with classical music arrangements written by composer Luis Enriquez Bacalov. As the first effort in Italy to merge rock music with classical treatments, this album is still considered one of the most important Italian progressive rock releases ever.