Judas Priest singer Rob Halford dishes on Nostradamus

A symphonic heavy metal concept double album about Nostradamus may not rank among such conceptual classics as Pink Floyd's The Wall, David Bowie's The Rise and Fall of Ziggy Stardust and the Spiders from Mars, or the Beatles' Sgt. Pepper's Lonely Hearts Club Band, but when the band making Nostradamus is Judas Priest, epic ambitions pose no risk. They are already in the pantheon of metal gods, progenitors of the genre who are right up there with Black Sabbath. Fans will flock to their shows no matter what, and the band's upcoming "Metal Masters" concert at Cricket Pavilion boasts a lineup that doubles as a who's who of influential metal bands: Testament, Motörhead, Heaven & Hell (a.k.a. Black Sabbath with Ronnie James Dio), and Judas Priest.

Among them all, they've been making metal for 40 years, selling more than 78 million albums worldwide. "It's a really special moment, to get these bands together," says Judas Priest singer Rob Halford, speaking from a hotel room in Washington, D.C., on the second night of the tour. "It's a bit of rock 'n' roll history because it'll never happen again, and it's only for a limited amount of North American dates."

The tour is as exceptional as Nostradamus, a two-CD, 23-track journey through the life of the controversial, 16th-century prophet via strings, synthesized guitars, and atmospheric musical interludes set alongside Priest's screaming twin-guitar assaults and steady, cannon-boom percussion. Lyrically, the album is more biographical/philosophical than ethereal.

"We could have done two kinds of records," Halford says. "We could have focused on the prophecies and visions — because he had many, many of those — or we could do what we ended up doing, which was to talk a little bit about his personal experiences."

"Five hundred years ago, he was going through some tough times," Halford continues. "He was rejected by a lot of people who thought he was dabbling in the black arts . . . the church authorities looked down on him and banished him into exile. He got looked on as a bit of a freak, you know? And we thought, 'Oh, that's what we felt like sometimes, in heavy metal.'"

Halford also points out that Nostradamus was, in fact, a metalhead. "[He] also dabbled in alchemy, the process of trying to turn base metals into gold. He had a kind of metal laboratory, working silver and gold and copper. So, he was a metalhead!"

And what does Halford think about Nostradamus' alleged psychic abilities and prophecies? "I don't really know," he says. "There are people that believe in the 'Phoenix Lights,' you know? I try to keep an open mind. I just think he's a very intriguing, mysterious man, and I think the fact that we're talking about him 500 years later is pretty remarkable."