Black Sabbath is an English rock band, often credited with being the first heavy metal band. Its music has had a considerable, extensive influence over the genre, from the band's formation in Birmingham in 1968 to the present day. Originally, the band's music was a dark amalgamation of blues and psychedelic rock, but quickly developed into the sound recognizable today, setting the template that would be adhered to by many heavy metal and rock bands in the 1970s and 1980s.
It is known to non-fans primarily for the controversy arising from the perceived gloominess of its music and lyrical themes and, more specifically, the erratic on-stage (and, eventually, off-stage) behaviour of frontman Ozzy Osbourne. It is also known for having undergone numerous line-up changes. Surprisingly, however, the band is currently comprised of three of the original members; Tony Iommi, Terence "Geezer" Butler and Osbourne.