Question: When did the highly experimental musical style on the album Quixotic originate?
Context: Ulver (Norwegian for wolves) are a Norwegian experimental musical collective founded in 1993, by vocalist Kristoffer Rygg.  Their early works, such as debut album "Bergtatt", were categorised as folklore-influenced black metal, but have since evolved a fluid and increasingly eclectic musical style, blending genres such as rock, electronica, symphonic and chamber traditions, noise, progressive and experimental music into their oeuvre.  1997 marked their international debut with the release of their third album "Nattens madrigal" through German label Century Media.  However, following discord with the label, Kristoffer Rygg formed his own imprint Jester Records in 1998.  British composer and multi-instrumentalist Daniel O'Sullivan joined the collective in 2009, and the band performed some of their first live concerts in their 15-year lifespan, including the prestigious Norwegian National Opera. The Baschet Brothers refers to two French brothers named François Baschet (born 30 March 1920, in Paris; died 11 February 2014) and Bernard Baschet (born 24 August 1917, Paris; died 17 July 2015) who collaborated on creating sound sculptures and inventing musical instruments, such as the "Cristal Baschet".  François Baschet was a sculptor and Bernard Baschet an engineer.  The Baschet Brothers invented the inflatable guitar, the aluminum piano and many other experimental musical instruments.  They created an "Baschet Educational Instrumentarium" for exposing young people to musical concepts.  .  The Baschet‘s research started in the 1950s artistic turmoil, soon turning the two brothers into the pioneers of sound sculpture, in addition to making them highly requested by musicians, composers, experimental directors. Quixotic is the debut album by English singer-songwriter Martina Topley-Bird.  The album spans several musical styles including trip-hop, electronic and rock.  It was co-written and produced by Topley-Bird and received positive reviews from music critics upon its release and was shortlisted for the 2003 Mercury Music Prize.  "Quixotic" also includes a collaboration with musician Tricky, with whom Topley-Bird collaborated prior to her solo work. Murat Brierre or Murat Briere (1938–1988) was one of Haiti's principal metal sculptors.  He was influenced by George Liautaud, but his work acquired its own, highly experimental style, often focusing on multi-faceted and conjoined figures, fantastically personified elements, and unborn babies visible within larger creatures.  He sculpted works that reflected both Christian and Haitian Vodou themes.  His works have been displayed in the United States, Mexico, Jamaica, and in Haiti's National Pantheon.  Brierre was born in Port-au-Prince. A Thousand Leaves is the 10th studio album by the American experimental rock band Sonic Youth.  It was released on May 12, 1998, by DGC Records.  "A Thousand Leaves" was the band's first album recorded at their own studio in Lower Manhattan, which was built with the money they had made at the 1995 Lollapalooza music festival.  Since the band had an unlimited amount of time to work in their studio, the album features numerous lengthy and improvisational tracks that were developed unevenly.  Three highly experimental extended plays, "", "", and "", were recorded simultaneously with the album. Moods is the eighth studio album by Neil Diamond, released by Uni Records in 1972.  It contained the second of his #1 songs, "Song Sung Blue", and was something of a follow-up in style to the highly experimental "Tap Root Manuscript". Experimental Musical Instruments was a periodical edited and published by Bart Hopkin, an instrument builder and writer about 20th century experimental music design and custom made instrument construction.  Though no longer in print, back issues are still available.  The material and approach of EMI can now be found electronically on their site hosted by Bart Hopkin.  This site is, together with www.oddmusic.com the main source on the internet for experimental musical instrumentalism. The following is an incomplete list of experimental music festivals, which encapsulates music festivals focused on experimental music.  This list may have some overlap with list of contemporary classical music festivals and list of electroacoustic festivals.  Experimental music is a compositional tradition that arose in the mid-20th century, particularly in North America, of music composed in such a way that its outcome is unforeseeable.  The Groupe de Recherches de Musique Concrète (GRMC), under the leadership of Pierre Schaeffer, organized the First International Decade of Experimental Music between 8 and 18 June 1953, and the phrase was used by musician John Cage as early as 1955.  Afterwards saw the development of specific experimental musical instruments, which were featured at various music festivals.  Musique concrète is an experimental form of electroacoustic music, and free improvisation or free music is improvised music without any rules beyond the taste or inclination of the musician(s) involved. Prostitute is Toyah Willcox's 1988 album.  It is a concept album and highly experimental in nature, marking a considerable divergence from previous works.  It is uncompromising in its style, and is presented as a continuous piece of music, although the notes in the CD version indicate "...to enable the listener to access a particular title a time-code programme has been provided".  To accommodate the two-sided format of the LP and cassette releases, side one--subtitled "Lie Down"--contains the first seven titles, and side two--subtitled "And Think of England"--contains the rest of the album.  No singles were drawn from the album. Trip hop (sometimes called "downtempo") is a musical genre that originated in the early 1990s in the United Kingdom, especially Bristol.  It has been described as "a fusion of hip hop and electronica until neither genre is recognizable," and may incorporate a variety of styles, including funk, dub, soul, psychedelia, R&B, and house, as well as other forms of electronic music.  Trip hop can be highly experimental.
Answer: the early 1990s