Question: When was the band that put out Under the Sign of Hell formed?

Context articles: The Blackwater Fever
True Norwegian Black Metal – Live in Grieghallen
This Is Hell Demo
Gorgoroth
Hell:on
Tennessee Pulleybone
Acid Witch
G.a.s. Drummers
Under the Sign of Hell
God Seed

The Blackwater Fever are an Australian blues guitar-drums group, which formed in Brisbane in 2005.
 They were awarded "Best Blues & Roots Act" at the 2006 Sunshine Coast Music Festival.
 They issued their debut five-track extended play, "Abused Blues", in January 2006 by the founding duo of Shane Hicks on vocals and guitar; and Rick DeMarco on drums.
 The tracks had been recorded live-in-the-studio at OPM Studios, Brisbane.
 Hicks and DeMarco co-wrote "Blackwater", which provided the band's name, Hicks later recalled "[we were] brain storming for a band name we were having a hell of a time trying to come up with something.
 One of the first guitar/drums songs we wrote together was called ‘Blackwater’ and it’s about people catching a fever from drinking tainted water.
 Put all that together and you have our band name!
 We found out later that it was a term for severe malaria….
 And because we were going for a dark swampy bluesy sound, we thought….
 Perfect!"
True Norwegian Black Metal – Live in Grieghallen is Gorgoroth's first full-length live album, released by Regain Records.
 It was recorded live in the studio at Grieghallen Lydstudio in Bergen and Threeman Recordings in Stockholm.
 The songs on the album represented the most commonly played songs in Gorgoroth's live set.
 The cover design by Magnus Wohlfart was radically different from the previous three full-length albums, being more reminiscent of the cover of the album "Under the Sign of Hell" (1997).
 Most of the album was recorded before the departure of vocalist Gaahl and bass guitarist King ov Hell, who had intended on using the band's name and assets.
 The bass guitar for this album (originally performed by King ov Hell) was later re-recorded by guitarist and band founder Infernus.
 Infernus dedicated the album to the late Jon Nödtveidt of Dissection.
This Is Hell Demo was the very first physical release of songs recorded by hardcore punk band This Is Hell.
 The album was untitled and released on both CD and 7" vinyl formats, also in Europe on Broken Glasses Records (distributed by NO PANIC!
 Records now).
 All formats are out of print and difficult to find.
 The song "Wreck Your Life" was later released on a label sampler cd from Trustkill, the label that This Is Hell later signed to and released their debut full length "Sundowning," but not before a stint on State On Mind Recordings who released their self-titled EP.
 On that same song, the opening line of the lyric includes the band's name, and was possibly the inspiration for the name.
 The lyric reads: "Brandon put it best when he told me 'this is hell,' wiser words have never been said."
Gorgoroth is a Norwegian black metal band based in Bergen.
 It was formed in 1992 by guitarist Infernus, who is also the only original member remaining, and the band have since released nine studio albums.
 Gorgoroth are a Satanic band and have drawn controversy due to some of their concerts, which have featured impaled sheep heads and mock crucifixions.
 The band is named after the dead plateau of darkness in the land of Mordor from J. R. R. Tolkien's fantasy novel "The Lord of the Rings".
Hell:on is a Ukrainian thrash/death metal band formed in 2005 in Zaporizhia, eastern Ukraine by Oleksiy Pasko and Oleh Talanov.
 lyrics of the band generally deals with mysticism, philosophy and anti-religion.
 Hell:on has ranked among the top bands in the Ukraine metal scene.
 At the recording of the last three albums the band has worked with Jeff Waters, Andy LaRocque, Marek Pajak, Andreas Kisser.
 Started from 2006, band played numerous live shows around all Europe, mostly in Poland, Czech Republic, Slovakia, Hungary and Germany.
 During the creative activity, the band recorded five full-length albums and one DVD.
Tennessee Pulleybone was a band formed in Cookeville, Tennessee.
 The original group featured "Big" Ken Smith (Bass), Jerry Tuttle (Instrumentalist), Biff Watson (Guitar), and John Wolters (Drums).
 Later members were Dave Gillon (Guitar), Tom Hamilton (Banjo), and Thomas "Bones" Kaelin (Drums).
 Their recording of "The Door Is Always Open" on JMI Records (Jack Clement International) hit the Billboard Country chart on September 8, 1973 and peaked at 75.
 Other singles on JMI Records were "I Ain't In A Long, Long Time", and "Clean Your Own Tables".
After JMI Records closed, the band went on to sign with RCA Records and began touring with Willie Nelson, Bobby Bare, Freddy Fender, Gary Stewart and numerous others.
 Still today they are often referred to as the first country band to sign to a major label.
 Some of their songs were written by Dave Gillon who also wrote hits for other artists such as Roy Clark, and Kenny Rogers.
Acid Witch is an American heavy metal band formed in Detroit, Michigan, in 2007.
 They released their first album, "Witchtanic Hellucinations", in 2008 on Razorback Records.
 The band then released two EPs, "Witch House" in 2009 and "Midnight Mass" in 2010.
 The band released their second album, "Stoned", in 2010, on Hell's Headbangers.
 In 2012, "Witchtanic Hellucinations" was re-released on Hell's Headbangers.
G.a.s. Drummers was a melodic hardcore band formed in Jerez de la Frontera, Spain at the end of 1997 by three teenagers who stood out from their other students due to their colourful hair dies and their taste in the california punk rock bands such as Bad Religion, Operation Ivy, NOFX, Lagwagon, The Descendents etc.
 Original members from other small local bands Dani Llamas (guitar and vocals), Pakomoto (Bass and vocals) and Rafa Camison (Drums) started playing together and composing their own music and after one year of sending demos around the country they got put as the opening act for Swedish Punk Rock band Randy on their Spanish tour.
 A tour that took the band through the whole country helping a lot of Spanish kids discover that there were actually Spanish bands capable of sounding as good as some of their favorite American bands.
 This lead immediately the band to sign to a young record label called Slide Chorus Records a young emerging record label from Madrid which would start releasing albums for other Spanish Punk Rock bands.
 This first release titled Proud To Be Nothing hit the streets at the end of 1999 and was presented on their first European tour which covered Spain, Great Britain, France and the Netherlands amongst Spanish punk rock legend[P.P.M.
Under the Sign of Hell is the third studio album by Norwegian black metal band Gorgoroth.
 Recorded in 1996 and released in 1997, it was the first album to feature Ares on bass (on one track) and the only one to feature Grim on drums.
God Seed was a Norwegian black metal band based in Bergen, Norway.
 Former Gorgoroth members Gaahl and King ov Hell adopted the name in March 2009 following the ending of the Gorgoroth name dispute.
 After performing a few gigs as God Seed, vocalist Gaahl left the band in July 2009 and it was put on hold.
 King finished the music for God Seed's first album, with vocalist Shagrath, and released it under the name Ov Hell.
 Gaahl re-joined God Seed in 2012.
 In January that year they released the live album "Live at Wacken", and in October they released their first studio album, "I Begin".