Nostradamus envisioned war, famine and apocalypse, but there's no way he could have predicted that in 2008, a British heavy metal band from the '70s would make a concept album about him.

Judas Priest didn't really see it coming either. It was a suggestion from manager Bill Curbishley, and the band figured Nostradamus, being an alchemist, was all about the metal.

"We were just looking for something different to do," says guitarist Glenn Tipton. "Every Judas Priest album has had its own character, really. We were just kicking ideas around. We talked about a concept album for quite a while, and our manager suggested we look into the life of Nostradamus, which we did. We were aware of prophesies, which most people are, but we didn't realize how interesting his life was. He suffered a lot of tragedy in his life and was exiled from the church and had to start a new life. That, combined with his visions and prophesies, made for a good story."

Judas Priest's own version of alchemy was putting Nostradamus' life to rock music.

"It wasn't easy," Tipton says. "When we started, we pretty much had a mountain to climb. The actual composition wasn't that difficult, because we had a lot of ideas. But to tell a story chronologically and lyrically and musically and make it work, all the moods work and preludes -- because there are 13 primary tracks and 24 tracks in all -- that was the difficult part."

One of the dangers of such a lofty project is that you'll veer perilously close to "Spinal Tap" territory, and there were, in fact, reviews that made the comparison. Tipton takes it in stride.

"People can compare it to whatever they want. After nearly 40 years in the business, if you don't have a sense of humor or a reality check ... we're not really worried about what people compare us to."

Hardcore fans of the old Judas Priest material don't have to worry about "Nostradamus" dominating the proceedings when the band plays the Post-Gazette Pavilion on Saturday in a metal fest complete with Heaven & Hell (led by Ronnie James Dio and Tony Iommi).

"We're doing about three numbers from the new album, and we'll probably add more as we go along. We didn't want to play too much from it until people get used to it, 'cause it's quite a bit to take in really and then next year we're looking to play it in its entirety at special events, special venues around the world."

Tipton joined Judas Priest around 1974, just prior to the band's debut album, bringing some of the musical undertones he absorbed from his mother, a classical pianist. Just using a second guitarist was an innovation for a metal band.

"We started after Thin Lizzy and bands like that, but I think we were the first band that had a duel lead guitar attack with trade-offs and searing solo harmonies -- I think we introduced that to metal and paved the way for that style of music. But we can't pat ourselves on the back and say we came out with that. It's just what we did, it was a natural progression."

Early on, with albums like "Sad Wings of Destiny" and "Sin After Sin," Judas Priest built a reputation as a pioneer of speed metal, second only to Black Sabbath on the metal pecking order. As the '80s rolled around, the band started churning out hits like "(You've Got) Another Thing Comin' " and "Living After Midnight."

"Tracks like that made us a household name, if you like," Tipton says. "But again, we've always believed there was room for melody in metal and there's room for far more in metal than people give it credit for. We've always tried to push the boundaries of metal to give us more room to maneuver and to give other bands more room to maneuver as well."

Judas Priest rode that mainstream success up until leather-clad singer Rob Halford rode off on his Harley in 1991 after the "Painkiller" album. They gave it a go with Tim "Ripper" Owens, a singer from a Judas Priest tribute band, but not much came of that, especially in the grunge era.

Then, in 2004, Halford reunited with Priest for Ozzfest, and the band picked up right where it left off -- although without the hits, of course. At 56, Halford still has a menacing physical presence and can still reach for the glass-breaking high notes.

"His tubes are great," Tipton says. "A lot of singers, the older they get, their voice starts to deteriorate. Rob's has stayed the same. We're fortunate that we're all still in shape. In a million years, I never thought we'd be around this long."