"Everyone wants to hear something miraculous but William Sinclair, who designed the chapel, was an architect, not a musicians," he said. "It is in triple time, sounds childlike, and is based on plain chant, which was the common form of rhythm at the time."

The Rosslyn Chapel has long been the subject of much speculation and even conspiracy theory; the recent novel The Da Vinci Code helped to popularize the notion that the chapel could be the hiding place of the Holy Grail or some other valuable object.

Mitchell plans to make a recording of the piece, but he must first assemble the rare medieval instruments for which it is scored.