Progressive metal, as a distinct musical style, was primarily advanced by members of the American heavy/power metal scene of the mid-1980s, particularly Queensrÿche, Fates Warning and, later, Dream Theater. These bands form the so-called triad, the "Big Three" of prog metal, or the most important and influential groups of the traditional scene.
The origins of the genre date back to the very beginning of heavy metal/hard rock and progressive rock, as some bands began to merge the two different approaches. 1960s pioneers like King Crimson maintained their musical innovation while incorporating a harder approach, using dissonance and experimental tones, yet maintaining a relationship to the power chords of hard rock. At the same time, metal/doom stalwarts such as Black Sabbath began to integrate accentuated progressive influences into pioneering records such as Sabbath Bloody Sabbath (1973) and Sabotage (1975).
Canadian trio Rush are widely recognised as bridging the gap between the hard rock period, English prog and the purely heavy metal genre. Initially influenced by Led Zeppelin, they evolved to combine established progressive rock technique with blues-based power chords. Records such as 2112 (1976), A Farewell to Kings (1977) and Hemispheres (1978) showcased technical expertise while utilizing a more direct approach than the established English prog rockers.
Other heavy metal bands of the era contributing to the genre include England's Iron Maiden and the Danish Mercyful Fate.
1984 brought full length debut albums from American bands Queensrÿche, from Washington, and Fates Warning, from Connecticut. Taking inspiration from established metal acts like Iron Maiden, each expanded their music to include more progressive elements (The Warning 1984, The Spectre Within 1985) – some through sound experimentation and compositional refinement, others through extremely complex structures and atypical riffs – up to the two seminal works in 1986: Rage for Order and Awaken the Guardian. In the following years the two bands, while following different paths – more basic and simple the first, more articulate and complex the latter - explore and expand the technical refinement and sonic finesse of their music, continuing to lay the foundations of the genre with important works such as Operation: Mindcrime (1988) by Queensrÿche, No Exit (1988) and Perfect Symmetry (1989) by Fates Warning.
Other important groups of 1980s prog-metal included Crimson Glory (Transcendence 1988), Heir Apparent, Savatage, and Canadian innovators Voivod.
Progressive metal also found a home in the burgeoning U.S. speed metal movement, influencing thrashers Metallica and Megadeth. "Math-metal" pioneers Watchtower, from Texas, took the concept of time-changes to a new level, combining thrash metal, syncopation and prog in their albums Energetic Disassembly (1985) and Control and Resistance (1989), giving rise to an extremely technical approach based on the rhythmic deconstruction typical of jazz fusion. This same type of prog metal will be later integrated into death metal by American bands such as Atheist (1991's Unquestionable Presence) and Cynic (1993's Focus). Among the other pioneering thrash metal bands, one of the most important is the Canadian Voivod, with their complex and experimental style, full of psychedelic dissonances (Dimension Hatröss 1988, Nothingface 1989).
The major second wave US bands that contribute to further delineating and developing the genre are Psychotic Waltz and Dream Theater. The former, with an approach halfway between Watchtower and Fates Warning, produced A Social Grace (1990), melding their signature sound with the psychedelic Into the Everflow (1992), while the latter explored the legacy of the bands that preceded them while advancing their personal style with When Dream and Day Unite (1989). Both albums focused on keyboards and band members' virtuoso instrumental skills, and their efforts resulted in two fundamental albums, that institutionalize classic progressive metal and a certain way of conceiving it - Images and Words (1992) and Awake (1994).
As for Europe, among the pioneers are the Germans Sieges Even, who, starting from the techno thrash of Watchtower, explore the more technical and angular side of progressive metal with
Steps (1990), followed the following year by the more melodic A Sense of Change (1991).
Among other important groups that have distinguished themselves for the peculiarity of the proposal: in the US, for the melodic and/or power side Shadow Gallery (Carved in Stone 1995), the neoclassical Symphony X (The Divine Wings of Tragedy 1997), Redemption (The Fullness of Time 2005), O.S.I. with Kevin Moore (ex-keyboardist of Dream Theater) and Jim Matheos (guitarist of Fates Warning); for the technical side Zero Hour (The Towers of Avarice 2001),
Power of Omens, Arch/Matheos (parallel project of Fates Warning), instrumental groups such as Spastic Ink, Liquid Tension Experiment, Gordian Knot and Canvas Solaris; for a more heavy approach Hammers of Misfortune (The Locust Years 2006) and
Heart of Cygnus; in Europe: for the melodic and/or power side the Norwegians Conception (Parallel Minds 1993) and Ark (
Burn the Sun 2001), the Germans Vanden Plas (The God Thing 1997) and Secrecy, the English Threshold, the Danish Royal Hunt (Paradox 1997), the Swedes Andromeda (
II = I 2003) and Evergrey (In Search of Truth 2001), the Poles Riverside (Out of Myself 2003), the Spanish band Avalanch; for the technical and/or experimental side the Norwegian Spiral Architect, with their innovative approach between Watchtower and Fates Warning in [
A Skeptic's Universe (2000), Twisted into Form, Leprous (Tall Poppy Syndrome 2009) and Frantic Bleep. Among the groups outside the European-American context are the Australians
To Dimension Logic, 1994).
Among the bands of the late 1990s who managed to bring innovation to the scene, thanks to a strong personality and a substantial discography, there are the Dutch Ayreon, a project by Arjen Anthony Lucassen, and the Swedes Pain of Salvation: they've helped redefine the canons of traditional progressive metal. The first one through theatrical and melodramatic rock operas (Into the Electric Castle 1998, The Human Equation 2004), interpreted by numerous singers and arranged together with many musicians, the latter referring to the eclecticism and anti-conformism of Faith No More, always looking for an unusual style (One Hour by the Concrete Lake 1998, BE 2004). An experimental and alternative approach, that in prog metal sees Thought Industry (
Mods Carve the Pig: Assassin's Toads and God's Flesh 1993), Mind over Four, and Voivod as forerunners. Another important and key figure for electical and unusual prog is the singer, guitarist and composer Devin Townsend, who brought the vanguard attitude to highest levels within this genre (Terria 2001).
As of 2018, the genre is still constantly evolving in multiple forms, and has reached a far broader variety of sounds and styles than it had at its origin, with many of the historical bands continuing to record new music and tour, while thousands of other new bands emerge in the underground scene every year, from all over the world. Recently, Mastodon and Gojira are two examples of progressive metal starting to reach mainstream popularity.