“[He’s a] guy who died 500 years ago but is still talked about today,” says Judas Priest guitarist Glen Tipton. “He left his mark.”

Tipton is referring to Nostradamus, revered alchemist, prophesier and now subject of the legendary British heavy metal quintet’s latest album. Comprised of 24 tracks and having taken a full two years to complete, Nostradamus (Epic) represents two firsts for Judas Priest. Prior to this, they’ve never attempted concept or double studio albums before.

“We’d considered doing a concept album before, around (2005’s) Angel Of Retribution,” Tipton says. “After reading up on Nostradamus, though, we were quite inspired by his life story — the tragedy of losing his family to The Plague, the mysteries surrounding his prophecies and his renowned alchemy. There was a lot to intrigue us to tell his life story. By the time we were done, we had two albums worth of material.”

As albums go — Priest or otherwise — Nostradamus is quite an earful, not to mention way off the beaten path. While still swathed in Priest’s trademark sound and style, Nostradamus is orchestral, almost operatic metal. Its two-dozen tunes are segmented into 13 primary tracks linked together by a variety of preludes, interludes and other devices. It still sounds like Priest, thanks to Tipton and K.K. Downing’s fretwork, singer Rob Halford’s distinctive nasal projection and the downbeat-heavy rhythms of bassist Ian Hill and drummer Scott Travis, but this is a far cry from the simplicity of “You’ve Got Another Thing Coming.”

“It’s a dramatic story, so we wanted to relate it in a classic, operatic way,” Tipton explains. “We stepped into areas that Priest doesn’t normally step into. We composed some of it on keyboards, which lent a new angle, and then transposed it to guitar. We’re looking for grandeur; [an] operatic, classical type of thing, almost like a film score. Funny enough, it ended up as classic Judas Priest. It’s always a risk to do something different in this day and age, but at the same time, we believe people will give it a chance. Step into the world of Nostradamus. There’s a lot to be enjoyed.”

Produced by himself and Downing, Tipton admits that while Nostradamus is decidedly verbose, it is still pared down from the band’s initial vision. Fuelled by fascination, the Birmingham crew faced the monumental task of fitting the story together coherently, chronologically and with interesting flow, hence the two-year production time.

“I think that because it was so inspiring, we were quite prolific,” says Tipton. “The trick was piecing it all together. We wanted to tell the story fluently, lyrically and musically. Piecing the music together took the most time, but it was all quite natural. I think that’s because with his life there were highs and lows. Every section of music had to create the mood for that part of his life. Whether you believe in his prophecies or not, he’s clever to have come up with so many that could or could not be true even today. Musically, that made for quite a revelation. We did discard a lot, though. People don’t realize that you discard as much as you write. It has to be musically relevant. The music has to capture the moment in life you’re relating.”

Recognizing the weight and peculiarity of Nostradamus, Tipton confesses that despite each song being a part of an overall whole, the band will only be playing a small selection of its tracks on their tour. Riding the line between satiating fans with favourites from their 18-album catalogue and promoting their latest work, Judas Priest will wait to discern the album’s acceptance before committing to live renditions of the work.

“At the moment, we’re just doing three tracks from the album, but next year we hope to perform it in its entirety if it’s received well,” he says. “We’ll make an event of it in special venues around the world and supplement it with musicians and singers, or orchestrate it. We’ll steer away from full orchestration, because it’s been done so many times and this album has far more character than that.”

Judas Priest are playing at the Monsters of Rock festival, alongside Ozzy Osbourne, The Dillinger Escape Plan, Voivod and others.