How Ozzy Osbourne and Black Sabbath found their sound – and invented heavy metal

The band’s manager, Jim Simpson, organised a series of stunts to maintain interest.

At the Marquee Club, he sent a pair of stilt-walkers dressed as the Devil to mingle with the crowd, providing the band with a pungent aroma of sulpher throughout their set.

Another time, he booked the band on Top Of The Pops and arranged for a giant inverted crucifix to rotate behind them during their performance.

While some cried blasphemy, the band loved the controversy.

“Everyone talks about love, peace and harmony, man, but you know, it don’t exist,” said Osbourne in an interview during that period. “We’re the hard end of it.”

But the band were more than simply a gimmick. Future generations of musicians would cite them as a key influence, and their shadow would hang over generations of heavy metal bands.

From the choppy riffs of Soundgarden to the demonic howl of Slipknot, Sabbath would reverberate through the decades, a reminder that rock music could be both terrifyingly visceral, and breathtakingly beautiful.

Yet, by 1979, Sabbath were in danger of becoming a parody of themselves.

Osbourne’s unreliability was starting to test the patience of his bandmates and his bandmates were starting to tire of his constant pranks and bad behaviour.

A series of musicians drifted in and out of the group and the band lost its focus.

Osbourne, in particular, was pushing the self-destruct button – being arrested or fined for a series of what would later be revealed as staged drunken escapades.

After leaving the band in 1979, Osbourne worked out that the answer was to sober up and go solo. His manager, Sharon Arden (later his wife), was instrumental in pulling him out of his downward spiral and focusing him on a new project.

By the end of the decade, he had released his first solo album, Blizzard of Ozz, masterminded the US Festival, and finally given himself a voice he could control – although his behavior off stage would remain predictably unpredictable.

It was a remarkable transformation, which saw him transcending the limits of Black Sabbath, and becoming a fully-fledged rock star in his own right.

But the band he started didn’t die off when he left.

In his absence, the remaining members pushed forward, recruiting Ronnie James Dio on vocals to produce a run of albums that, while never reaching the same heights of success as their Ozzy-led predecessors, have gained a cult status all of their own.

That was, perhaps, the secret of Black Sabbath’s 50-year success. By constantly reinventing themselves, and adapting to changing tastes, they ensured they would remain reverberating through rock’s back catalogue as one of the most enduring and influential bands of all time.