It can be a tricky affair to reconcile black metal with its creators – to strip away the mystique, the darkness and the otherworldly allure that radiates from the speakers and consider the circumstances and personalities that actually went into the creation. For instance, 'Woman Of Dark Desires', the third track on Bathory’s third album Under The Sign Of The Black Mark might appear to have been beamed in directly from a place of primitive malice and menace, yet who would have ever guessed that it was loosely based on ‘Machine Gun’, the decidedly unpretentious and workmanlike ditty from Barnsley transport cafe metal titans Saxon, taken from their Wheels Of Steel album?

Similarly, just as the sleeve to Under The Sign Of The Black Mark is now hailed as a classic sleeve image, the reality of the situation – as revealed by the alarmingly candid black metal progenitor Quorthon AKA Tomas Börje Forsberg RIP – was him striking a deal with the Swedish National Opera to leg it onstage for a matter of minutes to utilise the staging of the second act of their production of Carmen to photograph a bodybuilder friend of his in a papier-mâché devil mask.

Quorthon, the architect of this essential black metal document, was 20-years-old at the time of the making of Under The Sign Of The Black Mark, and although he was perhaps unaware of the repercussions that the work he was doing would have on a whole legion of black metal warriors in the future, he was painfully aware that the music he was making and the vibrations emanating from the studio in late 1986 were somewhat out on a limb. It was enough of a struggle even finding like-minded individuals to join the band, with him having to resort to sending letters to drummers from Artillery and Sodom in an attempt to get them to contribute, alongside bass players from across the Atlantic, all attempts at wooing such collaborators ultimately proving futile.

“Extreme metal of the sort Bathory was all about back in the early and mid-80s, was still unheard of in Sweden at that time,” he related on Bathory’s official website. “The style and sound of Europe was considered the only way back then, and Bathory was anything but party and love lyrics or poodle hair and spandex. So why should these guys spend a split second of their lives to even think about joining my little pathetic noise act, when the prospect of getting laid, getting a international deal and sell out the Budokan, was much more likely in a Europe copy-cat band than in something like Bathory? I really felt out of place back then.”

1986, the year this unholy document’s creation was recorded before its release on May 11 1987, was a peculiar year for metal whichever way one looks at it. Besides the Aquanet and Clairol dominance of the like of Bon Jovi and Europe, finally – with the release of landmark albums like Metallica’s Master Of Puppets and Slayer’s Reign In Blood – thrash metal was starting to be taken seriously as more than a juvenile tantrum by the metal press (at least beyond fanzines and the UK’s Metal Forces). The genre leaders, apparently intent on some evolutionary shift beyond the style they’d forged, were experimenting with guitar synths, bigger production values and pop sensibilities, as on Iron Maiden’s Somewhere In Time and Judas Priest’s Turbo, with somewhat mixed results. It stands to reason that the strange kind of alchemy that was taking place at Heavenshore studio in Huddinge, near Stockholm (a converted garage by any other name, in which the house engineer was Quorthon's dad) generated a great deal of its power and potency by being made in splendid isolation.

There certainly may have been a lineage to the vitriolic attack and grandiose dimensions of Under The Sign Of The Black Mark – like so many Swedish musicians, Quorthon’s first love was KISS, and their anthemic bravura and knuckleheaded monstrousness can be clearly detected within these grooves, whilst Venom, another band who took KISS’ caveman charm and showbiz stomp as a jumping-off point, are another clear antecedent.

Yet this album marks an important fork in the road, whereby the nascent black metal sound emerged as something beyond the blood-gargling grand guignol of the style that the latter three Wallsend-birthed warriors had volleyed forth with on the Black Metal album. Something with more purity of intent, yet also paradoxically a good deal more finesse and sophistication even amidst the nightmarish tumult of sound.

The beer-swigging tongue-in-cheek aspect that Venom brought to the table was nowhere to be found amidst these sepulchral grooves and feverishly croaked serenades and even when Chopin’s time-honoured funeral march is nicked for the harmony break in ‘Call To The Grave’, it’s with a poker-faced intensity that grants it complete conviction. Moreover, even when guitar and drum sounds are amateurish and wonky, and keyboard parts seemingly drafted in from a Casio are employed on the aforementioned 'Woman Of Dark Desires', all are deployed with alchemical force that stubbornly navigates this black-sailed vessel far from the lands of mirth and ridicule.

Reading the last rites though, black metal ultimately and fundamentally finds its power in atmosphere, and this is something Under The Sign Of The Black Mark has in spades, from the creepy and lo-fi intro 'Nocturnal Obeisance' (that seldom-used word only adding yet more leftfield vibrations to the equation) via the viciously monomaniacal bite of 'Equimanthorn', through to the long, comparatively slow and strident 'Enter The Eternal Fire', whose thundering groove and epic, longboats-to-Valhalla tone set a template both Quorthon himself and legions of admirers would follow. It was essentially the blueprint for what would become Viking metal and would also have a considerable impact on Emperor's neo-classical sturm-und-drang to boot. Here was proof that Bathory weren't simply about speed, excess and depravity at all costs; they could sculpt something cinematic and bombastic without sacrificing one iota of their bloodthirsty brute force.

Like the druids of Stonehenge in Spinal Tap lore, more or less nobody knew who Bathory were, or what they were doing. Quorthon never performed live, and besides a few slightly incongruous record store meet-and-greets and some photo shoots for which he apparently was happy to drag an animal bone covered in rotten flesh through the prying eyes of customs and international airport security, rarely appeared in public. Yet even besides such part-deliberate, part-accidental mystique, its considerable legacy remains due to clarity of vision and singular intent, and is more than proved with the testimonies below from heavy metal veterans themselves, Paradise Lost, Epica and Katatonia, to contemporary advocates of Bathory's raw power, Dread Sovereign, Grand Magus and Abigail, to young blood like Black Moth, Dragged Into Sunlight, White Hills and Winds Of Genocide, who are making their name in extreme music today. Under The Sign Of The Black Mark stands tall, and as strong 30 years on as the day a skinny young KISS fan got on the overground to meet his dad in a suburban garage in the chill of autumn.

“Under The Sign Of The Black Mark was and still is in my top ten albums of all time. The first time I heard it, it blew my mind how evil it sounded. Songs like 'Massacre','Woman Of Dark Desires' and of course 'Equimanthorn' were so good/evil that they started an entire genre. I know some say Venom started black metal because of the title of their second album but if you listen to any of the subsequent second and third wave of black metal – I don't recall ever hearing the term as a genre until the early-90s anyway – they all sound like fairly weak versions of Bathory's early work. I am not a fan of black metal as such but Under The Sign Of The Black Mark is a genre defining, groundbreaking album. I like all Bathory's first four albums but Under The Sign Of The Black Mark is the defining moment for me.”

Gregor Mackintosh, Paradise Lost/Vallenfyre

“This album defined the future of black metal. Put on any modern black metal album (or any form of blackened metal) and you'll hear Bathory's influence, and most of all, the influence of Under The Sign Of The Black Mark immediately! Black Sabbath created the future sound of heavy metal, Bathory created the future sound of black metal.”

Rob Van Der Loo, Epica

"Bathory has been one of the most important bands for me personally and also for Grand Magus as a band. The later Viking-era of Bathory is of course the main influence when it comes to what Grand Magus are doing, but when I heard Under The Sign Of The Black Mark for the first time it really got to me and it has stayed with me ever since. I loved The Return...... but it didn't prepare me for Under The Sign Of The Black Mark. It's just on another level of power, atmosphere and riffs, and to have such memorable songs all the way through, is an incredible achievement with music this extreme. So many have rightly pointed out that this is really the blueprint for the whole Scandinavian black metal thing that happened in the early 1990s, but it's crazy just how fundamental this album is. It created a whole genre on its own. And then Quorthon created another genre with Hammerheart just a few years later! Hail Quorthon!"

JB Christofferson, Grand Magus

“To me Under The Sign Of The Black Mark is the definitive black metal album. It epitomises the term in every aspect and Quorthon was doing things in Bathory and on that album back then that no one else was or had ever done before. A true pioneer and a true pioneering and genre-defining album that had an obvious and huge influence on the second wave of black metal bands such as Emperor, Mayhem and Darkthrone, to name but a few bands who took the template Quorthon initially laid down both musically and vocally. Those bands brought his sound into the 90s and in turn to a wider audience. Then these bands introduced a whole new generation of extreme music fans to the pioneering sounds and influence of Quorthon. Under The Sign Of The Black Mark whilst remaining potent and primitive also marked the transition into more atmospheric, melodic and epic musical territory and was the crossroads between the punked-up evil of the first two Bathory albums and the epic grandiose majestic darkness of Blood Fire Death and the Viking-era albums. Venom might have coined the term black metal but Quorthon and this album perfected it. Quorthon sounds fucking possessed on this album which is often imitated, never bettered. The blueprint for black metal as we know it today and 35 minutes of some of the most essential evil metal to ever exist!”

Kat Shevil Gillham, Winds Of Genocide/Lucifer's Challice

“Under The Sign Of The Black Mark is still the ultimate black metal album. Quorthon's high screaming vokills, primitive lead guitars, non-stop speed drums, anti-heavy guitar riffs, beautiful keyboards... many black metal followers – including me – are doing this style. No melody line? Who cares! Quorthon is legend [that] never dies! 'Massacre' and 'Of Doom' are high speed, zero-melody black metal tunes. 'Woman Of Dark Desires' is the first symphonic black metal song. Also the album's Thanks List is very interesting! I really love this album. Fuck off and die Japanese poser metal magazines! Bathory: the name of black metal kings.”

Yasuyuki, Abigail

“Under The Sign Of The Black Mark made such an impact on me when I started playing guitar. They had this raw, visceral dark energy that I don't think has never been matched by another black metal band. But it wasn't just about the heaviness – songs like 'Woman Of Dark Desires' and 'Call From The Grave' were haunting and terrifying, influencing my style and desire to write fast heavy riffs. Together with Slayer and Venom they used to scare that shit out of me... and I loved it. They had that dangerous, forbidden appeal, that was especially seductive growing up in a family of Italian Catholics.”

Federica Gialanze', Black Moth

“Under The Sign Of The Black Mark was the first Bathory album that had a relevant and direct influence on Katatonia. Probably because the emphasis was leaning towards a way more heavier/epic side of black metal, particularly with songs like 'Enter The Eternal Fire’, 'Call From The Grave’ and 'Woman Of Dark Desires’. The album became a strong influence in our humble beginnings, what probably divided us from everyone else was that we were simultaneously inspired by both the black metal albums as well as the Viking albums that followed. I think the sum of these pounding songs on Under The Sign Of The Black Mark actually paved way for the Viking style that culminated on Hammerheart. I also heard that 'Nocturnal Obeisance’ was supposedly the original album title, which is intriguing, but it would be weird imagining this classic album with a different title today. R.I.P Quorthon! Long live Bathory!”

Anders Nystrom, Katatonia

“The first time I heard Bathory I felt as if my skull had been torn open by a chainsaw. From that point on I was a different man. VALHALLA!”

Dave W, White Hills

“Without doubt some of the most influential black metal and extreme music there is. Bathory were consistently ahead of trends and peers as well as attracting endless coattail riders. Originally taking influence from gritty punk such as Discharge and GBH rather than the polished and popular sound at the time, Bathory developed what would be a pioneering sound for black metal, and one which continues to evolve today. One of Bathory's finest moments is Under The Sign Of The Black Mark. Often cited as the Reign In Blood of black metal, Under The Sign Of The Black Mark remains as relevant today as it did in 1986, cementing its reputation as one of the most important black metal records of all time. Interestingly, Under The Sign Of The Black Mark was the third record, but it just hits like a shard to the jugular and if anything, purveyors of contemporary extreme music should take note on the basis that artists who can consistently deliver solid records are few and far between nowadays, most never even reach their third record it seems!”

T, Dragged Into Sunlight

“Rough hewn violence and intent, a vicious and malign testament to the glory of testosterone from start to finish. If Venom doodled the plans on a napkin then Under The Sign Of The Black Mark is the final preparation for detonation carved in the skin with a rusty razor. Bathory drew up the blueprints for an entire generation of black metal musicians. Changing, chameleon-like, from album to album yet always being ahead of the game. 'Enter The Eternal Fire’ showed us all, trailed us by fire that you could slowly and deliberately march your way to the gates of hell, but wasn’t it ‘Bridge Of Death’ by Manowar anyway? Who knows? Either way it had its leather pulled tight and came loincloth approved. Hail to you Under The Sign Of The Black Mark and of doom…”

Nemtheanga, Primordial/Dread Sovereign