In 2009 a spectacular adaptation combining material from the first two albums was performed in Germany under the English title Excalibur: the Celtic Rock Opera, with great success.
The first part of an intended trilogy, Excalibur, La légende des Celtes blended musical styles and was performed by Roger Hodgson (Supertramp), Fairport Convention, Dan Ar Braz, Tri Yann, Angelo Branduardi, Didier Lockwood, Gabriel Yacoub.
[1] It is structured as a series of songs and instrumental interludes linked by narration, covering the birth of Arthur, the creation of Excalibur, his victory over the pagans, the rebellion of Morgana le Fay and Mordred, the search for the Holy Grail, and Arthur's final defeat and trip to Avalon.
In 2007 Simon released the second part of Excalibur, Excalibur II, l'anneau des Celtes ("Excalibur II: The Celtic Ring") with contributions from Jon Anderson (Yes), Alan Parsons, Barclay James Harvest, Maddy Prior, Jacqui McShee, John Wetton (King Crimson / Asia), Justin Hayward (The Moody Blues), Flook, Karan Casey, Fairport Convention, Andreas Vollenweider and Martin Barre.
The second part creates a mytho-history of the time before Arthur, describing the birth of Merlin after the loss of the happy land of Anwynn, portrayed as a physical fusion of Britain and Ireland.
Merlin and Uther Pendragon struggle to restore order and defeat the Formeriis invasion of Anwynn.