Black Sabbath are the undisputed godfathers of heavy metal. Beginning with their eponymous debut and seminal sophomore LP, ‘Paranoid’ (both released in 1970), the quartet from Birmingham, England, coalesced the scattered contributions of numerous bands (from Blue Cheer to Led Zeppelin) into the powerful, uncompromising and surprisingly malleable style we recognize today. After a succession of influential albums, Sabbath guitarist Tony Iommi, bassist Geezer Butler and drummer Bill Ward parted ways with singer Ozzy Osbourne in 1979, and, for a brief time, enjoyed nearly as much success with former Rainbow vocalist Ronnie James Dio, at the helm. But the band’s fortunes took a turn for the worse after Dio’s departure, steadily declining into obscurity while Osbourne’s solo career flourished, until a reunion of the original foursome was finally brokered for touring purposes in 1997, and, in 2013, for the recording of Black Sabbath’s latest album, ’13’ (minus Bill Ward). Now, with a career spanning nearly five decades, and through thick and thin, Black Sabbath remain the benchmark by which all heavy metal bands measure themselves.