Sir Orfeo as being a parallel dimension to the everyday world rather than the Land of the Dead as in the Greek myth of Orpheus and Eurydice. The ability to move between one world and the other distinguishes the tale as told in its various British versions such as "Sir Orfeo" and the Shetland ballad "King Orfeo" where the captors are envisaged as inhabitants of a parallel fairy domain rather than as the infernal region of the Dead ruled over by Hades as in the Greek myth. Katharine Briggs sees the tale as related in British folk narratives as being equally influenced
The Mask of Orpheus with the Orpheus myth decaying. "The Mask of Orpheus", in addition to vocal and orchestral music, contains a significant amount of electronic music, (which was precisely composed by Birtwistle, and realized on his behalf by Barry Anderson). Each act has its own electronic "aura", which goes on continuously, sometimes prominently, sometimes inaudibly; the voice of Apollo is heard on several occasions as an electronic sound "speaking" in an invented language. These electronic sounds were made by Anderson in Paris at IRCAM. There are also six purely electronic interludes created by computer manipulation of harp sounds. Jocelyn Herbert was commissioned to