There are two main distinct eras of Black Sabbath. Firstly, there was the initial Ozzy Osbourne-fronted period from the band’s conception and formation in 1968 up to a few years after the release of Technical Ecstasy in 1976. Shortly after came a Ronnie James Dio-led era, which started when the band hired the former Rainbow singer in 1979 — though Dio would depart and rejoin the band several times. Osbourne would also later rejoin the pioneering heavy metal band in 1997 for their reunion tours.
Osbourne was fired in 1979 for his erratic behaviour and dependency on alcohol and drugs. The entire band were essentially abusing narcotics, but guitarist Tony Iommi claimed that Osbourne “was on a totally different level altogether,” he said, adding: “We were all doing a lot of drugs, a lot of coke, a lot of everything, and Ozzy was getting drunk so much at the time. We were supposed to be rehearsing and nothing was happening. It was like, ‘Rehearse today?’ ‘No, we’ll do it tomorrow.’ It really got so bad that we didn’t do anything. It just fizzled out.”
Osbourne’s departure from the band led to a new sound for Sabbath, which occasionally bordered on power-metal, as expected with a vocalist like Dio at the helm. On Dio joining the band after Osbourne’s departure, Iommi claimed: “They were totally different altogether. Not only voice-wise, but attitude-wise. Ozzy was a great showman, but when Dio came in, it was a different attitude, a different voice and a different musical approach, as far as vocals. Dio would sing across the riff, whereas Ozzy would follow the riff, like in ‘Iron Man’. Ronnie came in and gave us another angle on writing.”
By the late 1970s, Sabbath had been arguably the biggest metal band in the world for around a decade. Their stardom not only led to the toxic and intoxicated behaviour that would inevitably contribute to the many lineup changes of the band, but also to them being able to record in the homes of some of the most famous musicians ever to grace the earth, most notably recording ‘The Mob Rules’ in the home of John Lennon.
Iommi once revealed: “[‘The Mob Rules’] was done in London, in John Lennon’s house, actually. We recorded it in his studio there – the initial one. We wrote the song in the room where John Lennon did the ‘Imagine’ video – that white room with a piano in it. That’s where it was written, and then we ended up recording it there, as well – in different rooms. But, when we’d done the Mob Rules album, we’d done a different version [too] – because Martin Birch wanted to re-record it, so it’s all in the same vein, all in the same block. Because Martin Birch was not the original one – we used John Lennon’s engineer at that time.”
He added: “And we used the equipment that was there – I think I used an AC30, Geezer used whatever bass amp that was there, and Vinny had his drums set up in the hallway of the house. So, we had mics around the house in different rooms.”
‘The Mob Rules’ also contains one of Iommi’s favourite guitar riffs of the Sabbath Dio era – a thoroughly rocking bluesy riff indeed – though Iommi also admitted that he wrote it using a technique with which he was not normally accustomed: “[Using a tremolo bar] was very unusual for me,” Iommi said, “Because I never used to use them. Obviously, nowadays, everybody uses them. I’m not really good with them – it was just a divebomb. That was it. I think I had an SG with a tremolo at that time.”