They will witness German composer Giacomo Meyerbeer's 1831 grand opera "Robert le Diable" (Robert the Devil), a work so rarely performed that virtually no one has seen it, let alone sung it or played it.

In fact, the last time Britain's prestigious Royal Opera House put on the epic work was in 1890, by which time it had fallen out of favour, never to recover fully.

"I think the piece still works today," said Laurent Pelly, the French director with the Herculean task of staging a work that turned Meyerbeer into a superstar when it premiered in Paris nearly two centuries ago.

"I hope they will be taken by the story and the music and the singers," he told Reuters backstage on the eve of opening night. "It's a huge piece."

The chorus is 80-strong, there are 10 dancers, and the principal singers face roles among the most demanding in opera.

Adding to the stress was a last-minute casting change for the key role of Isabelle, which was to have been performed by American soprano Jennifer Rowley in her Royal Opera debut until she was replaced less than a week before the premiere.

"It was a musical problem," Pelly explained. "We were doing five weeks and in the end it was not possible to do, so it was very important to find somebody else," he added, speaking in English.

Italian Patrizia Ciofi was brought in with the advantage that she had worked with Pelly before and, crucially, was one of the few sopranos who had previously performed Robert le Diable.

"Three days is very short of course, but I know Patrizia," Pelly said.

Ciofi will sing the first four performances (December 6, 9, 12 and 15) and Russian soprano Sofia Fomina will take over for the final two shows on December 18 and 21.

PARIS TRIUMPH

When Meyerbeer started work on Robert le Diable, he set out to create a hit. Pelly likens the opera to a Hollywood blockbuster, light on subtlety but rich in action, special effects, stirring music and melodrama.

Set in the times of knights, jousting and chivalry, the story follows Robert's quest for the hand of Isabelle and his dangerous dance with the devil, and contains the once notorious scene of nuns' ghosts dancing provocatively by their tombs.

The effect on audiences in 1831 was sensational. They fell in love with the opera, which quickly became a favourite around the world and was deemed a masterpiece by Frederic Chopin.

Degas captured it in paint and, according to Pelly, its influences can be traced to popular works by composers including Bizet, Offenbach and Gounod.

Why it had fallen from grace by the 20th century is not clear.

"During the 19th century a lot of composers were inspired by Robert le Diable and by Meyerbeer, and 60 or 70 years after it seemed very old fashioned, there were too many performances and everybody knew it," said Pelly.

"I think the opera-goer wanted to forget it."

Other factors included the expense of staging such a large work, the emerging talents of Wagner and Verdi and its running time of over four hours. Except for Sunday's matinee, there are, unusually, plenty of tickets left on the Royal Opera website.

Some experts link its decline to Wagner, who was heavily influenced by Meyerbeer early on but turned on the composer and sought to disassociate himself from him. (Reporting by Mike Collett-White)

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