Aha, nice topic to make some contorversy. The Tony Martin era.
Started with "The Eternal Idol" when it was clear that Iommi solo project ("Seventh Star") plagued by misjudgement of the label and bad mangement led to the dissolution of the remaining Black Sabbath as it was known between 1970-1978 (Ozzy era), 1980-1982 (Dio era I), and 1983 (Gillan era). I'm not counting the singers that didn't record. So 1987 saw an album under the moniker Black Sabbath (without anything else) some Tony Martin on vocals and some people helping on bass, drums and the faithful keyboardist Geoff Nichols (non credited as part of the band up to "Reunion" in 1996, shameful!)
Following "The Eternal idol" a not very much BS album (not doomy or gloomy), came in 1989 a wonderful album "The Headless Cross" (I got in vinyl with the sticker and the whole
enchilada 
), now Martin vocals are much more solid and defined. With Cozy Powell on drums and some Laurence Cottle on bass the band delivered a great heavy, dark, maybe among the most obscure lyrically albums. The came "Tyr" (1990) a departure from the "satanic/religious" lyrics into more myhtological (Norse) fields, also featuring a ballad type different from the classics 'Changes' and 'She's Gone' or 'Over And Over', a ballad more according to the American type of metal accepted at the time as commercial ('Feels Good To Me'), and a new bass Neil Murray. Then came the interregnum with Dio, Appice and Butler again ("Dehumanizer" 1992
), only for the project to fall apart (Halford finished the tour, any live bootleg of BS with him will be subject of mass murdering in order to get it from my part
). "Cross Purposes" saw martin again at the helm with Butler still on and Bobby Rondinelli on drums, then a live album "Cross Purposes Live" (I don't consider it official and therefore I don't have it, I heard it and I didn't like the production) and then "Forbiden" in 1995 with Powell and Murray in the rythm sectiom. Produced by Ice-T guitar and with the collaboration of the rap/metaller, the album is the biggest crap in BS history and a sad way to end the Martin era (the only reason is still in my collection is due to completism).
The Martin era (not counting the Dio II gap) went from 1987-1995 (7 years) so Martin was more in BS than Dio was (4 years) and close to Ozzy (8 years), so basically Tony Martin have more rights in Black Sabbath than people we consider
rightfully in the band IMO.
A couple of favs form each Martin album
"The Eternal Idol": 'Glory Ride', 'Lost Forever'
"Headless Cross": 'Headless Cross', 'Black Moon'
"Tyr": 'The Lawmaker', 'Valhalla'
"Cross Purposes': 'Immaculate Deception', 'The Hand That Rocks The Cradle'
"Forbidden": 'Shaking Off The Chains', 'Rusty Angels'
someone's got Maiden on the mind! Seventh STAR you mean!
