Question: Who founded the Dutch Symphonic metal band who released the album Black Symphony?

full_context: Document 1: Enter (Within Temptation album): Enter is the debut studio album by Dutch symphonic/gothic metal band Within Temptation, released by DSFA Records in 1997. The album prominently features lead singer Sharon den Adel's vocals as well as guitarist Robert Westerholt's gruff death metal growls. Lex Vogelaar, founder of the Dutch death metal band Orphanage, supplied the guitar parts for "Pearls of Light", as well as producing the album, and Orphanage vocalist George Oosthoek performed some of the growls on "Deep Within".
Document 2: Live i Oslo Spektrum: Live i Oslo Spektrum is a live album released on CD, DVD and Blu-ray featuring Norwegian alternative rock band Kaizers Orchestra. It features their concert at Oslo Spektrum in Oslo, Norway on 9 April 2011, the official celebration of Kaizers Orchestra's tenth anniversary. The album is expected to be released on 11 November 2011 (coinciding with the release date of their eighth studio album, "Violeta Violeta Vol. II", and the stage premiere of their musical, "Sonny"). The live CD of the same concert, bundled with both releases, omits a certain number of songs due to capacity constraints.
Document 3: Black Symphony: Black Symphony is a live album, DVD and Blu-ray Disc from Dutch symphonic metal band Within Temptation. It was released worldwide on September 22–24, 2008 and is available on 2-disc DVD, 2-disc CD, and Blu-ray.
Document 4: Martijn Westerholt: David Martijn Westerholt (born 30 March 1979 in Waddinxveen, Netherlands) is the cofounder (along with Charlotte Wessels), keyboardist, and the main songwriter of the Dutch symphonic metal band Delain. He was previously a member of symphonic metal band Within Temptation, until he was diagnosed with infectious mononucleosis shortly after the release of Within Temptation's second full-length studio album, "Mother Earth". His brother Robert Westerholt is the guitarist and founder of Within Temptation. He currently lives in Zwolle, where he resides since his study in Communication at Windesheim College in 1998.
Document 5: Within Temptation: Within Temptation is a Dutch symphonic metal band founded in April 1995 by vocalist Sharon den Adel and guitarist Robert Westerholt. They have always been classified by critics as gothic metal, although the "gothic" influence varies with each album. Their most prominent and well-known sound is described as symphonic metal, although their earlier material, such as debut album "Enter", was mostly gothic metal. "Enter" even had a hint of doom metal. In an interview, Den Adel said they fell into a symphonic rock genre with various influences. In a later interview with Dutch music platform 3VOOR12, den Adel stated that "we consider ourselves more a symphonic rock band ... in my opinion, we are no gothic band".
Document 6: Robert Westerholt: Robert Westerholt (born 2 January 1975 in Waddinxveen, South Holland, Netherlands) is a Dutch musician, known as the guitarist, unclean vocalist and co-founder of the symphonic metal band Within Temptation. He also writes music for the band along with his partner and band vocalist Sharon den Adel. He used to work in human resource management before his career with Within Temptation.
Document 7: Sharon den Adel: Sharon Janny den Adel (born 12 July 1974) is a Dutch singer, songwriter and fashion designer, best known as the lead vocalist and one of the main songwriters in the Dutch symphonic metal band Within Temptation. She has been a performing musician since the age of 14, and was a founding member of Within Temptation, along with Robert Westerholt, in 1996.
Document 8: Elect the Dead Symphony: Elect the Dead Symphony is the first live album by System of a Down frontman Serj Tankian. It is available in CD, CD/DVD, LP, and Digital Download formats. It features the Auckland Philharmonia Orchestra at the Auckland Town Hall in Auckland, New Zealand. Orchestral arrangements were by John Psathas. Material for the performance is from Tankian's solo debut, "Elect the Dead" with some additional previously unreleased songs.
Document 9: Nightwish discography: The discography of the Finnish symphonic metal band Nightwish consists of eight studio albums, one extended play, four live albums, seven compilations, thirteen music videos and twenty one singles. The band was formed in 1996 by songwriter and keyboardist Tuomas Holopainen, guitarist Emppu Vuorinen, and former vocalist Tarja Turunen; Nightwish's current line-up has six members although Turunen has been replaced by Anette Olzon, and the original bassist, Sami Vänskä, has been replaced by Marco Hietala, who also took over the male vocalist part. Olzon left the band in 2012 and was replaced by Floor Jansen.
Document 10: Live Inferno: Live Inferno is the final release from the band Emperor. It was filmed during the band’s sold out 2005-2007 reunion performances. It was released in Europe on 20 April with several editions available. It is available as a 2CD slipcase with 16pg booklet, a limited edition Digibook featuring 2 CDs & DVD with an enhanced 24pg booklet, a single DVD, and two limited edition double vinyl gatefold sets. The audio portion of the "Live Inferno" series features exclusive recordings from the band's headlining performances at Norway's Inferno festival and Germany's Wacken Open Air festival. The video portion, titled "Live at Wacken Open Air 2006 - A Night Of Emperial Wrath", has a running time of 70 minutes and includes footage professionally filmed at the Wacken Open Air festival with additional on-stage and exclusive backstage footage filmed and compiled by the band.
Document 11: Collected (Black 'n Blue album): Collected is a five disc Black 'N Blue box set, released in 2005, with 4 audio CDs and one DVD. This release contains the first four studio albums released by the hard rock/ glam metal band, Black 'n Blue. The DVD contains an entire live concert performed by Black 'n Blue, containing most of Black 'n Blue's hits, while also including a few songs that were never released on any Black 'n Blue disc. These include "Run Run", "Summer Heat", and "Rock n' Roll Animals", which later became "Knocking On Heaven's Door".
Document 12: Hydra World Tour: Hydra World Tour was a concert tour by Dutch symphonic metal band Within Temptation in support of their sixth studio album, "Hydra", released by Nuclear Blast on 31 January 2014. To date, it was their eight major tour and their third to see them playing worldwide. The tour passed over four continents and was divided into several legs according to the local of playing, presenting minor setlist variations from concerts of the same leg and a few more variations from leg to leg. A special leg was entitled "Theatres on Fire", in which saw the band playing seated shows exclusively on theatres. The tour was commercially successful and managed the band to play on even bigger spaces, an improvement already seen on their last world tour, as well presenting their first concert at the Wembley Arena and selling out theatre tickets for their theatre seated concerts in the Netherlands. A live album with footage from the Amsterdam concert was released later in 2014 under the name of Let Us Burn – Elements & Hydra Live in Concert.
Document 13: Nightwish: Nightwish is a symphonic metal band from Kitee, Finland. The band was formed in 1996 by lead songwriter and keyboardist Tuomas Holopainen, guitarist Emppu Vuorinen, and former lead singer Tarja Turunen. The band soon picked up drummer Jukka Nevalainen, and then bassist Sami Vänskä after the release of their debut album, "Angels Fall First" (1997). In 2001, Vänskä was replaced by Marco Hietala, who also took over the male vocalist role previously filled by Holopainen or guest singers.
Document 14: Hand of Sorrow: "Hand of Sorrow" is a song by the Dutch symphonic metal/rock band Within Temptation taken from their fourth album "The Heart of Everything". The song is part of the promotion for their 2008 live DVD, "Black Symphony", according to their web page, as well as "Forgiven", which was released as a single.
Document 15: Delain: Delain is a Dutch symphonic metal band formed in 2002 by former Within Temptation keyboardist Martijn Westerholt, and Charlotte Wessels. The name of the band comes from the Kingdom of Delain in Stephen King's novel, "The Eyes of the Dragon".
ground_truth: Sharon den Adel and guitarist Robert Westerholt