Original line-up: Ozzy Osbourne (vocals), Tony Iommi (guitar), Geezer Butler (bass), Bill Ward (drums)
The band started in Birmingham, England in the late 60s as Earth before changing their name. Initially a blues playing band Black Sabbath became one of the definitive classic heavy metal bands, to be ranked alongside Led Zeppelin and Deep Purple.
With a competent rhythm section and the extraordinary antics of Osbourne the band enjoyed success with their British metal of brutal riffs right from their first album, the eponymous Black Sabbath (1970). Their second album Paranoid (1970) made them an success in America. Both the albums's tunes and covers marked the band as influenced by the occult and 'black' magic.
They released a further three albums, Master of Reality (1971), Black Sabbath Volume 4 (1972) and Sabbath Bloody Sabbath (1973) before management problems and the label change from Vertigo to WWA ruined the bands schedules in 1973. The next album Sabotage was not released until 1975 and the follow-up to that, Technical Ectasy (1976) was the last album in the heavy Sabbath style.
In 1978 the band released the lacklustre Never Say Die and rumours that Osbourne was to leave the band were proved true in 1979 (Osbourne formed Blizzard of Ozz, swiftly renamed to Ozzy Osbourne Band). He was replaced by Ronnie James Dio but it was the end of an era.
and someone else can write 1979 to date
The band rarely received any critical praise ("blundering bozos" was one description) and Osbourne vocal talent can be safely labelled as exuberant but non-existant. Despite this their fan-base of 'Sabs' was large and fanatical.