Bathory was a Swedish extreme metal band formed in Vällingby in March 1983. Frontman, founder and sole songwriter Thomas "Quorthon" Forsberg was the sole constant member, and was at times responsible for all instruments.

Named after Hungarian countess Elizabeth Báthory, Bathory is considered a pioneer of black metal (alongside Venom, Hellhammer and Mercyful Fate) and Viking metal. The book Lords of Chaos described Bathory's first four albums as "the blueprint for Scandinavian black metal."

The band stopped performing live early on in its career and never toured. Bathory dissolved when Quorthon died from heart failure at the age of 38 in June 2004.

Bathory formed in Vällingby on 16 March 1983. Quorthon, a 17-year-old guitarist (then known as "Ace Shoot", a name inspired by sex jokes, two Motörhead songs – "Ace of Spades" and "Sharpshooter" – and Ace Frehley of Kiss), was joined by bass guitarist Frederick Melander ("Hanoi") and drummer Jonas Åkerlund ("Vans McBurger"). Åkerlund has stated that he and Melander, his cousin, were the original members of Bathory and that Ace, as he was known at the time, joined later on, when they were looking for a new vocalist/guitarist.

According to Quorthon, he settled on the name 'Bathory' after a visit to the London Dungeon, although Åkerlund says that it was also inspired and taken from the Venom song "Countess Bathory". The Venom song was based on the life of Elizabeth Báthory who is believed to be one of the most prolific female murderesses. Quorthon worked part-time at the small record label Tyfon Grammofon, which was owned by his father, Börje "Boss" Forsberg (1944-2017). In late 1983, the label was putting together a compilation of songs by Scandinavian metal bands. However, at the last minute, one of the bands backed out. Tyfon agreed to let Bathory appear on the record as a replacement. The album, called Scandinavian Metal Attack, was released in March 1984 and was Bathory's first appearance on record. Unexpectedly, the two Bathory tracks "Sacrifice" and "The Return of Darkness and Evil" drew a great deal of fan mail.

Soon afterward, Tyfon asked Quorthon to record a full-length album. His bandmates having moved away, Quorthon recruited Rickard Bergman from his former oi-punk band Stridskuk as bassist and Stefan Larsson from punk band Obsklass as drummer. On 22 May 1984, they had their first and only rehearsal together before recording the album. Two songs were recorded at the 22 May rehearsal: "Witchcraft" and "Satan My Master" making it the first recording of the debut album line-up. The debut album, Bathory, was recorded in June at Heavenshore Studio (a converted garage) in Stockholm and released in October that year. Over the next four years, Bathory released a further three albums: The Return...... (1985), Under the Sign of the Black Mark (1987) and Blood Fire Death (1988).

Bathory's early work was dark, fast, heavily distorted and raw recording (lo-fi). Quorthon's vocals were harsh, high-pitched and raspy with occasional shrieks and screams. The band's lyrics focused on 'dark' topics and included anti-Christian and 'Satanic' references. These traits came to define black metal and the band used this style on their first four albums. Quorthon said that the band were not Satanists but used 'Satanic' references to provoke and attack Christianity. With the third and fourth albums he began "attacking Christianity from a different angle", realizing that Satanism is a "Christian product" and seeing them both as "religious hocus-pocus".

Quorthon described Bathory's early sound as a "mixture" of Black Sabbath, Motörhead and GBH, singling out GBH's album City Baby Attacked by Rats and Motörhead's Ace of Spades and Iron Fist, and was also influenced by the Exploited, Sex Pistols, Disorder, Riot/Clone, Anti-Nowhere League, Kiss, Anti Cimex, Asocial, Mob 47 and Exciter. The term 'black metal' came from Venom's 1982 album of that name. Many fans and reviewers have claimed Venom was an influence on Bathory, or even accused Bathory of copying Venom. Quorthon often denied being influenced by Venom and claimed that he "heard Venom for the first time in late 1984 or early 1985" and never owned a Venom album. However, he admitted in an interview for Metal Forces that he first listened to Venom's Black Metal in 1983 and considered it "one of the best albums ever made." Bathory's early sound has always been associated with Slayer but Quorthon denied being influenced by them.