[4] He started his career in 1999 at age 19 and swiftly gained wider recognition with the release of trance single "Horizons", which he created with the freeware software Buzz.

His remix credits for this period include artists such as Madonna,[7] Britney Spears, Depeche Mode,[8] New Order, Nathan Fake and Kieran Hebden & Steve Reid.

[17] These shows consisted of Holden performing on modular synth alongside drummer Tom Page (of experimental electronic duo Rocketnumbernine and The Memory Band).

[10] This array of musicians allowed Holden to create a “spiritual jazz band playing folk / trance music” whilst keeping his "ever strident synth... front and centre".

[20] Other collaborative releases include Outdoor Museum of Fractals with Camilo Tirado, Three Live Takes with Houssam Gania and Long Weekend with Wacław Zimpel.