Question: When did the symphonic black/industrial metal band that formed in 1987 in Sion release their fourth album?

Context paragraphs:
Cyber metal: Cyber metal is a subgenre of industrial metal music which incorporates numerous elements found predominantly in EBM and Aggrotech, including the use of more melodic and less repetitive riffs, in opposition to mostly metallic and mechanical sound of industrial music.  First coined by industrial metal group Fear Factory in 1990, the vocals of cyber metal are harsh, ranging from singing techniques typical for aggrotech to black metal shrieks and death metal growls.  Guitar melodies are played in a similar way to melodic death metal, and keyboards specific to symphonic black metal are frequent as well.  Some bands like Deathstars, fascinated by the symbolism of totalitarianism, using it as part of the image also incorporated same aesthetic to their sound.

Carach Angren: Carach Angren ( ) is a symphonic black metal band from the Netherlands, formed by two members of the now-defunct bands Inger Indolia and Vaultage.  They have three steady members with previously frequent guest appearances for the violin parts.  Their style is characterized by prominent use of orchestral arrangements.  All of their studio albums are concept albums with lyrics based on ghost stories and folk lore, such as "Flying Dutchman".  They set themselves apart from other symphonic black metal artists in showcasing songs often using multiple languages apart from English, such as French, German and Dutch, though every song does use English as a baseline and certain choruses or sections will make the transition.

As the Angels Reach the Beauty: As the Angels Reach the Beauty is the second studio album by the symphonic black metal band Graveworm, released on 26 September 1999 through Serenades Records.  This is one of Graveworm's more symphonic albums, with strong symphonic metal influences and three symphonic interludes.  It was recorded and mixed at Newport Studios, St. Lorenzen, Italy and mastered at Newport Mastering Studios.

The Mother and the Enemy: The Mother and the Enemy is the fourth album release by the Polish symphonic black metal group Lux Occulta.  It expands upon the band's signature sound by incorporating influences from a variety of styles, including free jazz, trip hop, death metal, industrial music, electronica, and spoken word.

Hecate Enthroned: Hecate Enthroned is a British symphonic black/death metal band formed and based in Wrexham, Wales.  They formed in 1993 as a blackened death metal act under the name Amethyst, changing their name to Daemonum later on.  In 1995 the band changed its name to their current one and embraced a symphonic black metal style that was constantly compared to early Cradle of Filth, although since 1999 their work has strayed from their earlier symphonic black metal style and has incorporated more elements of melodic death metal.

Samael (band): Samael is a Swiss symphonic black/industrial metal band formed in 1987 in Sion, Switzerland.

Havoc Unit: Havoc Unit, formerly known as ...and Oceans, is an industrial black metal band from Finland.  It was formed in 1989 as a death metal outfit called Festerday, but soon changed its style to symphonic black metal.  It released its first album as ...and Oceans in 1998, and in the following years it pursued a less traditional, more industrial-oriented direction.  After ten years of existence as ...and Oceans and four full-length albums, the band changed its name to Havoc Unit in 2005.  Its first album under the new name was "h.IV+ (Hoarse Industrial Viremia)", released in 2008.  After five years, in 2013 band's name has returned to be Festerday.

Passage (Samael album): Passage is the fourth album by Swiss industrial metal band Samael, released on 19 August 1996 through Century Media.

Exile (Anorexia Nervosa album): Exile is the first studio album by the French symphonic black metal band Anorexia Nervosa.  It was released in 1997, through Season of Mist.  It is notable as the band's only industrial metal album, before they became a symphonic black metal band.  It is also the only album to feature Marc Zabé as one of the guitarists and Stéphane Gerbaut on vocals, as he was later replaced by R.M.S. Hreidmarr when the band decided to abandon the industrial metal.

Sodomizing the Archedangel: Sodomizing the Archedangel is an EP by the French symphonic black metal band Anorexia Nervosa.  It was self-produced, and released in 1999 via Osmose Productions.  It marks the transition from the band's previous industrial metal style to symphonic black metal, and is their first release to feature long-time vocalist Nicolas Saint-Morand (also known as R.M.S. Hreidmarr) and keyboardist Neb Xort.

Supporting paragraphs: Passage (Samael album) Samael (band)
Answer: 19 August 1996