With all due respect to all the great musicians who have performed under their banner -- especially Ronnie James Dio -- most fans agree there's only one true Black Sabbath lineup. But when singer Ozzy Osbourne went on to become far more commercially successful as a solo act than his bandmates after they fired him in 1979, the chances of a reunion seemed unlikely.

But that's just what happened, finally, in 1997, when Tony Iommi, Geezer Butler, Osbourne and (following a brief schedule conflict) Bill Ward reunited first as part of the Ozzfest tour and later at their own concerts. They have toured together sporadically since, but a planned 2012 world tour was scuttled first by Iommi's cancer battle and then by a dispute with Ward.

 

Watch Black Sabbath Perform 'War Pigs' in 1997