[Note: I am not a professional metal historian, nor a huge metalhead. However, to the best of knowledge, this information is accurate—also, sometimes even huge fans get facts wrong, so I wouldn't be alone in that regard if I messed something up.]
What is Bathory?
Named after the infamous "Blood Countess" Elizabeth Bathory, the band Bathory were pioneers of black metal, thrash metal, and so-called "Viking metal." In fact, Bathory's 1990 album, Hammerheart, is often considered the first Viking metal album. Their main member, Quorthon (Thomas Börje Forsberg), carried the bulk of the project's creative vision. In a way, Bathory was a constantly changing project, stylistically and otherwise, based on Quorthorn's interests.
For example, in the early days of Bathory, they were often attacking Christianity—utilizing Satanic lyrical themes and related album art. However, Quorthon came to see Satan as also being "religious hocus-pocus," so other themes became prominent. Also, some time in the mid-1980s, Quorthon decided to stop doing live shows, considering them too much of a hassle. Stylistically, Bathory had plenty of range, from thrash metal to slower, more atmospheric pieces. In fact, some of Quorthon's solo albums are said to be more straightforward alternative rock.
A multi-instrumentalist, Quorthon played guitar, bass guitar, keyboards, synthesizer, drums. He also performed the bulk of Bathory's vocals, which helped forge the black metal style.
Quorthon died at the young age of 38, presumably from heart failure.
Their First Album: Bathory (1984)
After replacing a band on the compilation album, Scandinavian Metal Attack, Bathory received a deluge of fan letters. Seeing potential, Bathory were encouraged to record a full length album for Black Mark/Tyfon records. Simply titled Bathory, it was recorded in a garage-turned-studio. The album is 26 minutes and 52 seconds long, due to the "thrash metal" style of the album (loud and fast).
With track titles like "Storm of Damnation," "Hades," "Reaper" and "In Conspiracy with Satan," you have an idea of what's in store. Also, the album cover is the head of a goat, so you know it's metal (interestingly, the "Yellow Goat" covers are considered valuable collector's items, as Quorthon stopped making them—he thought the color looked awful, so the black and white design is far more common).
While this album may seem like standard extreme, satanic thrash metal, it was a pretty unique sound at the time. Sure, things like hardcore punk existed before this album, and some of those bands bordered on a metal sound, but this album was harsh in a different way.
Ironically, although they were extreme at the time, Bathory is by no means the harshest sounding black metal experience (and, thankfully, they apparently weren't racist—unlike certain black metal bands). While Bathory (the album) doesn't offer the catchiest tracks, it is reasonably listenable, and fun to reflect on if you've got nothing else to do.
A Few Fun Facts:
On Bathory's first five albums, an outro indicated that "Bathory is crawling back under the rock but will be back"—which is both creepy and silly.
Jonas Åkerlund, music video director for Prodigy's "Smask My Bitch Up" and Madonna's "Ray Of Light," once drummed for Bathory.
In a 1987 interview with Hard Rock Magazine, Quorthon said their new bassist was talented, but acted too "bizarre," was institutionalized and had to be replaced. In the same interview he said, "If anybody is convinced that Bathory settles for some noise, then listen to the new album, and one will stop [assuming?] thrash and lack of musical practice."
In a 1987 interview with Metal Forces Magazine, Quorthon says: "I think it's totally wrong to put labels on a band's music because you should let the music speak for itself and it doesn't matter if you wear chicken bones, studded leather, spikes and upside-down crosses—the way you dress has nothing to do with the music at all. I mean, you don't play any better because you wear studded leather or not, do you?"