Together they came up with The Assassin Tree, a chamber opera with a mythological theme. The work begins its world premiere run tonight at the Edinburgh Festival and goes on next month to the Linbury Studio at the Royal Opera House in London.

According to The Scotsman, the pair took their inspiration from The Golden Bough, anthropologist James Frazer's examination of the rites and beliefs of various ancient cultures. The result is a neo-myth in which a King Priest of the goddess Diana is condemned to wait in her sacred grove for his successor, who must murder him in order to win office and the goddess's affections. (The titular tree is the site of the killing.) The successor must then take his turn awaiting his own assassin.

Soprano Gillian Keith sings the goddess Diana and baritone Paul Whelan is her King Priest; representing the next generation, as the Youth and the Slave, are tenors Colin Ainsworth and Peter Van Hulle. Garry Walker conducts the Britten Sinfonia in a production designed and directed by Emio Greco and Pieter C. Scholten, who made a big splash at the EIF in 2004 with their staging of Gluck's Orfeo ed Euridice.

The Assassin Tree runs for three performances at the Edinburgh International Festival (www.eif.co.uk): tonight, tomorrow and Sunday (August 27) at the Royal Lyceum Theatre. Then the Royal Opera House in London (www.roh.org.uk) presents the work in its Linbury Studio Theatre for three performances September 6-8.