LONDON (AP) ― If opera is a dead art form, somebody forgot to tell George Benjamin.

The English composer’s new opera, “Written on Skin,’’ has taken the music world by storm, hailed by critics, embraced by audiences and sprouting up in performance seemingly everywhere.

Since its premiere last summer in Aix-en-Provence, France, it’s been staged in London; Amsterdam; Toulouse, France; Vienna, and, most recently Munich, where a sell-out crowd cheered wildly after the last of three performances at the Prinzregententheater on Saturday night.

“The best opera written over the last 20 years,’’ was the assessment of critic Renaud Machard in Le Monde last July. Wrote Alex Ross in the New Yorker magazine this spring: “Even the composer’s most committed admirers are a little shocked. ‘Written on Skin’ feels like the work of a genius unleashed.’’

Curiously, for a work that many think may help point toward the future of opera, it’s in some ways a deliberately backward-looking piece.

Based on the legend of a 13th century troubadour, the libretto by playwright Martin Crimp tells of a nobleman, called the Protector; his young wife, Agnes; and an artist ― known as the Boy ― whom he hires to create a book illustrating his greatness. In those days before the printing press, manuscripts were painted by applying gold and other metals to parchment made from animal skin, hence the literal meaning of the title.

The plot moves swiftly to its tragic conclusion: Agnes and the Boy become lovers; the Protector learns of the affair, murders his rival and feeds his heart to his wife. Still proclaiming her love for the Boy, she leaps from a balcony to her death.

Benjamin had collaborated with Crimp on his first opera, the chamber piece “Into the Little Hill,’’ which premiered in 2006. He recalled how they settled on the subject for “Written on Skin,’’ which was a commission from the Aix-en-Provence Festival.

“Bernard (Foccroulle, the festival’s head) asked us to please situate it somewhere on the soil of Provence,’’ Benjamin said. “Martin’s daughter happened to be studying French medieval literature, and her professor came up with this story.’’

Both men found it appealing. “The strangeness is what attracted me,’’ Benjamin said. “The strangeness and the simplicity.’’

Those terms could well be applied to Benjamin’s score, which uses a large orchestra with some unusual instruments like glass harmonica, viola da gamba and bongos. “The idea,’’ he said, “is to make an orchestral radiance to suggest the art of illumination.’’

The libretto takes a story that’s already 800 years old and distances it still further by framing it as a tale told by angels who make frequent references to modern-day events. In addition, the characters speak of themselves in the third person and often utter their own stage directions.

Why use these multiple framing devices, instead of letting the plot unfold in a more traditional way?

“I couldn’t have done a straightforward narrative,’’ Benjamin said during an interview at his house in the Maida Vale neighborhood of London.

“I wanted to tell a story very directly because I think that’s incredibly important in theater,’’ he said, “but also I couldn’t use naturalistic dialogue, because in the age of the movies, when I go to many new operas today I always think: ‘Why are they singing?’

“Opera isn’t the naturalistic medium it was in the 19th century,’’ he continued. “Movies have done something to it. So you have to acknowledge that ... and this is a terribly simple technique, just putting things at a little distance.’’

Perhaps counter-intuitively, Benjamin said that for him, the artificiality had a liberating effect on his composing: “It allowed me to just forget about the issue and maybe be more spontaneous than I would be.’’

As an example he cited a moment that comes a half-hour into the opera, which runs about 95 minutes and is performed without intermission.