Formed in Norway in 1983 by Destructor (Oystien Åarseth, 1968, Norway, 10 August 1993, Oslo, Norway; guitar), who was a young fan of the Satanic black metal played by bands such as Bathory, Celtic Frost and Venom. Åarseth was joined in the original line-up by Necrobutcher (b. Jorn Stubberud; bass), Manheim (Kjetil Manheim; drums) and Messiah (vocals). Mayhem made their first impact with the 1986 demo Pure Fucking Armageddon, which is regarded in underground circles as a classic of extreme metal. The black metal genre was losing popularity, however, along with the leather-and-chains imagery and Satanic lyrics that were its trademark. Rather than follow heavy metal fashion and adopt the hardcore punk or death metal genres that were becoming popular, Åarseth (now known as Euronymous) opted to preserve purist black metal and founded the Posercorpse Music label. In 1987, with vocalist Maniac (b. Sven Erik Kristiansen) added to the line-up, Mayhem released their official debut Deathcrush, which featured six songs in 17 and a half minutes of frenzied angst. Maniac and Manheim were replaced by Dead (Per Yngve Ohlin, 1970, d. April 1991; ex-Morbid) and Hellhammer (Jan Axel Von Blomberg), but, in 1991, the former shot himself and Necrobutcher left the band. Rather than halting Euronymous's black metal crusade, Dead's suicide appeared to have redoubled his faith. He opened a record shop in Oslo named Helvete (Norwegian for "Hell") and relaunched his record label as Deathlike Silence Productions.

Mayhem inspired a number of Scandinavian bands to readopt the musical style and imagery of black metal during the early 90s, while Euronymous became an increasingly melodramatic and popular spokesman on the extreme metal underground, with his philosophies of cold hate and spite. A series of Norwegian church burnings in early 1993 were linked to the Black Metal Circle, a cult-like group centred around Euronymous's black metal crusade and dominated by members of bands such as Emperor, Darkthrone and Burzum, all signed to Deathlike Silence. Euronymous revelled in the international publicity. However, on 10 August 1993, he was found, stabbed 25 times, outside his Oslo apartment. Two weeks later, Varg Vikernes (better known by his stage-name of Count Grishnackh) of the band Burzum was arrested for the murder, and convicted the following year. Vikernes had been Euronymous's right-hand man, and it is not apparent whether the murder was committed because of a financial dispute over record royalties, over a woman, or because of darker doctrinal differences between the two. What does seem clear is that Euronymous was consumed by the vivid world of pain and hate he had himself created, while the black metal revival he inspired continues unabated. In 1994 De Mysteriis Dom Sathanas, was released posthumously. Sinisterly, it featured Grishnackh on bass guitar, alongside new vocalist Attila Csihar.

Hellhammer re-recruited Maniac and Necrobutcher and added guitarist Blasphemer (b. Rune Ericksen) to create the new Mayhem line-up. The quartet has continued touring and recording into the new millennium.

Biography courtesy of http://www.theiceberg.com