In 1973, Claude Deron and Daniel Denis, both former members of Belgian Zeuhl band Arkham (which had disbanded the previous year), set up a new group, Necronomicon.

Obvious early influences were Béla Bartók and Igor Stravinsky, but the band also cited lesser-known composers such as Albert Huybrechts, who was also Belgian.

In the interim, drummer Daniel Denis released two solo albums and joined Art Zoyd, a similar band from France.

They premiered at the fourth edition of the Rock in Opposition festival held in Carmaux, France in September 2011, where they performed "New York Transformations", a work composed by Kurt Budé.

Once Upon a Time in Belgium and Univers Zéro appear in the documentary film Romantic Warriors II: A Progressive Music Saga About Rock in Opposition.