ê_a Ira is set during early years of the French revolution; characters include Marie Antoinette, Louis XVI, and Marie Marianne—"the Voice of Liberty, Reason, and the Republic." It uses a circus as "a central theatrical framing device and metaphor," according to a statement released earlier this year.

The libretto was first written, in French, by songwriter Etienne Roda-Gil and his wife Nadine to mark the bicentennial of the revolution in 1989. Waters began work on a score at the time, but stopped when Nadine Roda-Gil died of leukemia. In 1997, he took up the project again and completed an English translation.

"Although it's rooted in the history of the revolution, its philosophical slant is, I suppose, contemporary as well," Waters said. "It's more than just a history of the French Revolution, it's a piece about the human potential for change."

Waters was a founder of the band Pink Floyd, with which he helped create the "rock opera" The Wall, among other bestselling albums.

Sony BMG will release a double-CD recording of the opera featuring baritone Bryn Terfel on September 27.