Black Sabbath is an English heavy metal band that formed in 1968 in Birmingham, West Midlands, England, United Kingdom, originally comprising Ozzy Osbourne (vocals), Tony Iommi (guitar), Geezer Butler (bass), and Bill Ward (drums). In the early 70s, they were the first to pair heavily distorted, sonically dissonant blues rock at slow speeds with lyrics about drugs, mental pain, and abominations of war, thus giving birth to generations of metal bands that followed in their wake. Their name itself taken from a notorious horror film, they are often credited with creating the heavy metal genre as well as the doom metal subgenre.
Black Sabbath was formed in Aston, a poor district of Birmingham damaged by bombing during World War II, under the name Polka Tulk Blues Band (soon shortened to “Polka Tulk”), later Earth. Initially a rockin’ blues band, Earth moved in a darker direction when the group, especially bassist Geezer Butler, being fans of the black magic novels of Dennis Wheatley, tried to make music to have the same effect as a horror movie or novel. Ozzy Osbourne wrote the lyrics to the second song they wrote together, “Black Sabbath” (the song name was inspired by a 1963 Mario Bava film), and Tony Iommi wrote a riff based on the tritone, sometimes called “Diabolus en Musica” (“the Devil in Music”).
Later in their careers, Geezer Butler would write most of the lyrics to Black Sabbath songs, taking direct inspiration from Ozzy’s instrumental ideas. In their Last Supper concert film, the band stated that the song is based on an experience Geezer had one night when he saw a black object at the end of his bed and noticed the next day that an occult book Ozzy had given him was missing.