All metal history properly begins with BLACK SABBATH. They, for all intensive purposes, invented metal. While other bands experimented with heaviness, none truly did it to the degree that Sabbath did, as early as they did, and as consistently as they did.
Black Sabbath played downtuned, loud, very heavy rock'n'roll. Moreso than any other band out there. What ties them to the foundations of black metal, however, is their lyrical content. They explored themes of mysticism and the occult. These themes would play heavily into the imagery of black metal in later years.
Metal developed a great deal in the 1970s. Hard rock and heavy metal bands continued to push the envelope and to broaden the musical horizons of the day. Bands such as Deep Purple, Motorhead, Rush, Blue Oyster Cult, Rainbow, and many others, continued to shape what we now call heavy metal. But black metal's next watershed event would come in the early 1980s.
In the late 70s, some English lads with a heart for metal got together and started making a new type of metal. Their metal was faster, and more raw than any other style out there (even Motorhead). These guys went by the moniker VENOM. Their debut album was 1981's Welcome to Hell. The listening public was floored. Now other band had attempted anything so visceral, so primitive. By today's standards, we would call it semi-competent speed metal with evil lyrics. But not back then.
This new evil needed a name. In 1982, Venom gave it a name by releasing their second album, Black Metal. This album (and Venom's style) spawned a host of imitators. But there were innovators yet to come. The most important of the innovators in the early 80s included Slayer, Hellhammer/Celtic Frost, Mercyful Fate, and Bathory.
Formed in California in 1982, SLAYER started off embracing Satanic themes and imagery. They played fast, raw thrash metal with eerie titles like "Black Magic" and "Evil Has No Boundaries." Like Venom, these songs focused on speed and a raw sound. However, the riffs were more focused, more technical than Venom's. Although their first three studio albums have come to be very influential among black metallers, Slayer went on to create more technical, more crisply produced speed-thrash beginning with 1986's Reign in Blood. Thus, Slayer's connection with black metal ends in that year.
Another important "pre-black metal" band was the Danish group MERCYFUL FATE. This group, formed in Copenhagen in 1981, focused on making evil music that had overtly Satanic imagery. The frontman of Mercyful Fate was a man who called himself King Diamond. King wore white-and-black face paint while performing and had a vocal range that surpassed all who had come before him. From high-pitched screams to low-end roars, King did it all. And he was not shy about proclaiming himself a Satanist.
From Switzerland came yet another early pioneer in the black metal sound. A trio calling themselves HELLHAMMER--formed in 1982--played raw and aggressive metal in the vein of Venom. After one official release, Hellhammer evolved into CELTIC FROST. Celtic Frost continued in the same style as Hellhammer, but with a more refined, more atmospheric sound.
Albums from the foundational/pre-black metal stage:
Of all of the bands to come out of the early 1980s, the one that has done the most for the development of black metal is Stockholm, Sweden's BATHORY. Fronted by the mysterious man known only as Quorthon (born one Thomas Forsberg), Bathory emerged sometime around 1983. Soon thereafter, some demo tracks began circulating in the underground. Bathory began to build a following.
Bathory's fame spread after two tracks appeared on a 1984 compilation entitled Scandinavian Metal Attack. That same year, Bathory released their self-titled album. 1985 saw another release, entitled The Return. This early Bathory material was raw and primitive. Their sound can best be described as somewhere near Venom or early Slayer, but much more evil.
This early sound perhaps reached its peak on their third album, 1987's Under the Sign of the Black Mark. This album contained material that was still aggressive and raw--like the earlier stuff--but the song structures were more varied. The guitar sound more closely resembles what we now think of as black metal. With classic songs like "Equimanthorn" and "Call From the Grave," Bathory set themselves apart from other Venom-imitators.
In 1988, Bathory further altered their sound with the release of Blood Fire Death. On this album, Bathory experimented with more varied tempos, better productions, and wrote truly epic songs. The songs from this period sound like they could almost be from an Enslaved album. Truly ground-breaking stuff. Metal reached a new plateau with Bathory's mid-period work. This was the birth of the sub-genre of black metal known as "Viking" metal.
Bathory has continued to release albums to this day. They have run the spectrum from raw and primitive Venom-worship, to a more polished and refined, yet epic metal. Bathory is probably the most important band in the history of black metal (at least in terms of influence).
Sadly, in the summer of 2004, Thomas "Quorthon" Forsberg was found dead in his apartment. He died of apparent heart problems. He was probably the single most important person in black metal history.
A Bathory Discography: