It's obviously impossible to pinpoint the exact moment when heavy metal was born, but exploring the genre's origins makes it crystal clear that classic rock artists had no small part in its development. Heavy metal's evolutionary chart plays out like a Who's Who of both hard and classic rock musicians. Trying to keep track of all the major players is hard work, so we've done the heavy lifting for you. With that, we bring you our tally of 11 Classic Rock Artists That Shaped Heavy Metal:

  • 11

    Iron Maiden

    Iron Maiden were pioneers of the New Wave of British Heavy Metal, a movement also featuring Motorhead and Def Leppard that was considered a revitalizing force following the eventual decline of bands like Sabbath and Zeppelin. ‘The Number of the Beast’ was the first album with singer Bruce Dickinson, and its self-titled first single, the quintessential Maiden cut.

  • 10

    Rush

    When it comes to popular progressive rock bands, Rush are at the top of the heap. The Canadian power trio’s first two albums -- 1974’s self-titled and 1975’s ‘Fly by Night’ -- were metal-tinged affairs; the former showcased the band’s love of Led Zeppelin and Cream, the latter featured the debut of drummer Neil Peart. It wasn’t until ‘Caress of Steel’ that they veered off into prog territory, clearly showing their intentions with the 20-minute, six-part epic ‘The Fountain of Lamneth.’

  • 9

    Motley Crue

    When Motley Crue burst onto the Los Angeles scene in 1981, they did so with a punkish sneer, a glam-metal sound and looks that certainly could kill. 1983’s 'Shout at the Devil’ showcased that edgy side in the strongest manner possible, and the band successfully gave into their hair-metal urges on later records, kicking off the power ballad craze with ‘Home Sweet Home’ off 1985’s ‘Theatre of Pain.’

  • 8

    Ozzy Osbourne

    After getting booted from Black Sabbath in 1979, Ozzy reinvented himself with a much glossier, radio-friendly sound, thanks in part to some fancy fretwork by the late, great Randy Rhoads. His debut, 1980’s ‘Blizzard of Ozz,’ features fan favorites 'Crazy Train,' 'Suicide Solution' and 'Mr. Crowley,’ and is his best-selling solo platter to date. The follow-up, ‘Diary of a Madman,’ was the last with Rhoads before his tragic death a year later.

  • 7

    Van Halen

    Eddie Van Halen and his famous homemade Frankenstrat guitar did some impressive things together on the band's 1978 self-titled album, most notably taking the generally accepted limits of guitar virtuosity and turning them on their ear. Van Halen were one of the last bands to have a revolutionary impact on metal, and Eddie’s monstrous metallic crunch and scorching lead solos -- not to mention his two-handed finger tapping -- are musical precision at its finest. The band will soon return with their first David Lee Roth-fronted album in over 25 years.

  • 6

    AC/DC

    More a rock band than a metal act, AC/DC powered their way through unforgettable fare like ‘Hells Bells’ and the title track from 1980s ‘Back in Black’ with cranked-up volume and intensity. They may not have contributed much in terms of new sounds to metal, but they certainly transmitted a primitive energy that was heard loud and clear. Some people might stick Guns N’ Roses in this slot, but we're sticking with the Aussie rockers.

  • 5

    Metallica

    Thrash masters Metallica dragged the underground thrash scene kicking and screaming (or more accurately, shredding and screaming) into the mainstream in the ‘80s with ‘Master of Puppets’ and ‘Ride the Lightning.' Soon after, 1991’s self-titled 'Black Album' made them international superstars, and they continue to be the reigning kings of metal to this day

  • 4

    Deep Purple

    Don’t forget Deep Purple, the criminally overlooked British hard-rock outfit with an undeniable influence on metal. Once dubbed the World’s Loudest Pop Group by the Guinness Book of World Records, DP were early pioneers of the form, with their 1972 album ‘Machine Head’ leading the charge. Guitarist Ritchie Blackmore’s effortless riffs made ‘Smoke on the Water’ an instant classic – and often the first song learned by aspiring metal guitarists.

  • 3

    Led Zeppelin

    Led Zeppelin weren’t heavy metal per se, but their heavy, blues-based rock sound certainly was a major influence on the genre. Although Zeppelin dabbled in many different musical styles, the lumbering, hard-hitting grooves of ‘Good Times Bad Times’ and ‘Dazed and Confused’ off their eponymous debut certainly paved the way for metal. The same could be said by the way for bands like Cream, Jimi Hendrix and even the Beatles -- if for nothing more than ‘Helter Skelter.'

  • 2

    Judas Priest

    There’s a reason they’re called “Metal Gods.” Judas Priest were there from the beginning, with singer Rob Halford and the boys emerging from the same area in England as Sabbath – and even sharing a rehearsal space back in the day. With Halford’s operatic vocals soaring over the twin guitarist assault of Glenn Tipton and K.K. Downing, Priest made a sonic stew that was frequently attempted and never duplicated, effortlessly staying ahead of changing trends in the genre. This diversity makes it hard to pick just one metal masterpiece from them, but 1980's 'British Steel' is a safe bet.

  • 1

    Black Sabbath

    When it comes to heavy metal, there’s Black Sabbath and then there’s … everybody else. With a sonic blueprint defined by down-tuned guitars, crawling tempos and singer Ozzy Osbourne’s distinct vocals, Sabbath influenced not only countless other bands but even entire metal sub-genres, from doom metal to thrash. They’ve sold more than 100 million records worldwide, with their self-titled debut and its follow-up ‘Paranoid’ (both 1970) frequently ranking among the most influential metal albums of all time.