In a recent interview with Kerrang, Black Sabbath guitarist Tony Iommi spoke about the differences within the band between working with original singer Ozzy Osbourne and his ultimate replacement, Ronnie James Dio.
"Well, I mean, the whole thing was different for us," Iommi said. "Because obviously, when Ronnie got involved, the writing became different because of the different sort of way he approached [music]. And it was a really exciting period for us… It sort of boosted us up. It was a bit of a challenge, but we enjoyed it."
Iommi was also asked if Dio was the number one choice to replace Osbourne, and it seems as though that was the case—although carrying on with the band was not as easy as it has been previously suggested, according to Iommi.
"To be honest, the way things were in the band at that point was fairly dismal, you know. Things weren't happening, and Ozzy really wasn't into it anymore. He was going through a lot of stuff at the time. And we had to either break up or replace him, which we didn't want to do. But it got to that.
"I met Ronnie a party probably a few weeks before that, and it was Sharon [Osbourne, then Arden], who introduced me to Ronnie. I actually talked to him about doing a side-project ourselves, something a bit different with the both of us. And he was into that.
"And then when Ozzy went, the first person I got in touch with was Ronnie. I said to the other guys, 'Why don't we try Ronnie, and see what you think?' This was when we lived in LA, so we got him over to the rehearsal room in the house. We had this one riff idea that we'd come up with, which was 'Children of the Sea,' [from Heaven & Hell] and Ronnie started singing something, and I just thought, 'That's great!' It was just such a different approach."
Asked specifically about that approach, Iommi commented, "[W]e could expand a bit more because obviously the way Ronnie approached stuff was different to Ozz. Ozzy was great, but Ronnie was a different singer altogether. We wanted somebody who was different, we didn't want to bring somebody in who was gonna sound similar to Ozz. So it was good to have somebody totally different, and Ronnie's voice and the way he approached the songs allowed us to be able to try different things in a different way than what we'd done before. It opened up a lot more variety for us, really."
Dio was a member of Black Sabbath from 1979 through 1982 before leaving, only to return again in 1991 to record the album Dehumanizer with Sabbath, which was released in 1992. Dio then departed the group for the last time shortly after. In the early 2000s, he reunited with his former bandmates under the banner Heaven & Hell for a series of tour dates. Sadly, Dio passed away from stomach cancer in May of 2010.