Black Metal was born in the early 1980s. The term originated with the NWOBHM band Venom, and was even the title of their second full-length album. That this trio from Newcastle represents the true beginnings of Black Metal there is no doubt. The hellish sound, raw and energetic playing, dark atmosphere and Satanic themes were present from their first release. And it was these last two points that were the real determining factors as to whether or not something would be categorized as Black Metal. If it was dark and Satanic, then that was all that it took to be worthy of such a label. Bands such as Mercyful Fate, Slayer, Hellhammer, Sodom and Bathory all joined the unholy war and were considered part of the same movement. While similar imagery played a part, the lyrical content and dark atmosphere were the main elements to be taken into consideration. However, over time, the definition of Black Metal evolved and the First Wave bands were later expelled or ignored by many. Despite bearing dark, Satanic and occult lyrics, many albums were disassociated from the movement that they created, or given the tag “proto-Black Metal”. Even Venom was lumped in with Thrash Metal and thus robbed of their legacy, to a degree. Albums like Show No Mercy, Don't Break the Oath and Seven Churches were disregarded, completely, when discussing Black Metal. If anything, Slayer was nothing more than a heavier, faster version of Venom with better musicianship. What more is needed when every single song includes multiple references to Satan and Hell? Even the first two Bathory records are frequently said to be more Thrash than Black. It is only the band's third album, Under the Sign of the Black Mark, that is considered as a pure Black Metal album and this masterpiece is in many ways the template by which many later recordings were patterned. Strange that even the very band that perfected what Venom started could receive such treatment, as it regards their earlier output. Much of the problem can be traced back to the early Norwegian scene, which is ironic since even the main figures of this movement knew that it was mostly the lyrical content that determined whether or not something was Black Metal.
Norwegian Black Metal began with Mayhem and this influential group was largely responsible for the shift in perception. As their musical style developed, they dropped a lot of the more primitive structures and riffs and began to utilize tremolo melodies and blasting drums. As Euronymous was a very important figure in the scene and Mayhem was well-respected, many others were inspired to play a similar type of music. Not only did they incorporate the riffing style and overall approach, but they were educated on the older bands and soon many were discovering the classic 80s releases. Burzum, Darkthrone, Immortal, Thorns and Emperor all exhibited some similarities (or influences from) with Mayhem, as well as many of the First Wave bands. The most important, by most accounts, would have to be Bathory. They also injected a lot of original thought and demonstrated a high level of creativity. Though each one could be easily distinguished from the other, they shared many characteristics and thus the modern definition of Black Metal was born.
It is true that the Norwegian bands helped revitalize Black Metal and to resurrect it. Through the combination of old school 80s influences and their own artistic vision, they created a distinctive sound that soon narrowed the overall style of Black Metal. After a certain point, things got confusing and this Scandinavian variant seemed to reinvent the sub-genre, altogether. However, this lead to many misunderstandings. Any band from Norway that shared aesthetic or musical tendencies were considered Black Metal, regardless of the lyrical content. Listen to the early albums from Immortal, Satyricon and Enslaved, for example. They had the look and the general sound of Norwegian Black Metal; i.e. the tremolo guitar riffing, the blast beats, the screeching vocals, etc. But they would be the first to tell you that they didn't play Black Metal because their lyrics were not Satanic. Immortal said that they played "Holocaust Metal". Satyricon called their brand of music "Medieval Metal" and Enslaved claimed to play "Viking Metal", though it sounded nothing like Bathory's Hammerheart album. For them, the lyrical content was as important, if not more so, than the sound. They even cited Deicide as Black Metal, simply because of the Satanic content of the lyrics. They called it 'commercial Black Metal', but Black Metal nonetheless. So it came to be that people looked to the Norwegian sound as the one that defined Black Metal, yet ignored the words of musicians such as Euronymous, Fenriz and countless others when they discussed the history of the music and actually gave credit to where it belonged; i.e. the First Wave bands.
With the passage of time, the lyrics and atmosphere became secondary. The sound and imagery were all that mattered. This resulted in countless bands coming along and espousing a message that had absolutely nothing to do with Black Metal, yet being considered a part of it because they play a certain way or wear corpse paint. Somehow, though their music is neither dark nor evil and has nothing to do with Satanic or anti-Christian themes, these fake bands managed to sneak in and join something that they cannot even begin to understand. It has gotten to the point where emo kids have been able to hijack certain elements, injecting them into their depressive goth-rock projects and still get labeled as some form of Black Metal when, in fact, it has nothing at all to do with it.
Obviously, labels can become subjective to the point of insanity. There comes a point between "Medieval Metal" and "Midnight Stroll By the Lake Near the Forest Metal" where someone has to draw a line. The narrower the categories, the more subjective it becomes as something can fit into several different sub-genres. In this case, the point is that some need to have more of an open mind and realize that bands represent different things to different people. The Norwegians did a lot for Black Metal, but they don't have the final say in how it is defined. It is done a little differently in Sweden and in the Czech Republic and in Greece and so on and each scene has its own sound. The beauty of the First Wave was that there were so many bands, including Venom, Slayer and Mercyful Fate that had similar themes and some of the same influences, yet they all had distinctive sounds. It is completely asinine for someone to come along and say that Mercyful Fate was not Black Metal, because it doesn't sound like the Second Wave stuff. Ironically, though they seem to worship the likes of Euronymous or Fenriz, they missed the point that both made on numerous occasions, regarding the definition of Black Metal.