What, exactly, is a midsummer night’s dream?

With the four-century history of Shakespeare’s play, the dream can be any warm-weather rite of self-discovery with no particular look and in no prescribed era. So the 1960 Benjamin Britten opera version, which plays at the Academy of Music Feb. 8-17, is within its rights to be an intensely colored netherworld with fairies sporting identical mustaches, green hair for many of the other characters, and beds that float in midair. With singers in them. Two to a bed.

“They turn their heads so that they look at each other and never have to look down. No vertigo,” said director Emmanuelle Bastet on Monday as she watched the scenery being loaded onto the academy stage. She has restaged the production around the world.

“You have to be in a place where you trust all of the people who are working there. Doing the production in Italy was a bit worrisome,” said bass Matthew Rose, a Curtis Institute graduate who plays the ham actor Bottom and who braved the elevated beds at La Scala in Milan.

Having originated in 1991 at Festival d’Aix-en-Provence, the celebrated Robert Carsen production with its sexually frank portrayal of romantic confusion among Shakespeare’s couples — plus comically inept fairies and an even more inept troupe of rustic actors — has traveled Europe and China extensively but is only now being seen in the United States.

That longevity doesn’t explain why the manic fairy Puck — a non-singing role played by actor Miltos Yerolemou, known for his portrayal of swordsman Syrio Forel in Game of Thrones — appears to have outgrown his costume. Other fairies are young and dapper. But in a typically original Carsen inspiration, Puck’s frenetic eagerness to please is evidence of his having gone to seed. It’s a long way from Mickey Rooney in the famous 1935 film version.

“I’m the guy who decided not to retire. This is the only job I have and I’m hanging on to it with all my might,” said Yerolemou. “That’s why Puck tries so hard and makes so many mistakes. Trying too hard is a sign that you’ve lost your touch.”

Whether or not Yerolemou brings in new audiences — he was new to opera until he landed in this one 15 years ago — the cast headed by Tim Mead and Anna Christy creates an overall package that should rival the Metropolitan Opera’s Midsummer. Few opera productions of any kind — much less nontraditional versions like Carsen’s — have “legs” like this one. Though long available on home video, it needs to be seen in person — and was in 2015 by the Opera Philadelphia team, which immediately began negotiations to bring it to the Academy of Music.

“It’s 28 years old but doesn’t feel it,” said Opera Philadelphia music director Corrado Rovaris. “It’s so fresh.”

Incongruously enough, the secret to visual lushness here is wool fabric: It covers everything with a deeply textured depth of color. Thus, the clean, simple, expansive set feels like a forest while hardly resembling one. “We didn’t want fake trees or vegetation. It’s a dream, and we wanted it to be that from the beginning,” said Carsen, whose commitments keep him from revisiting the Philadelphia revival. “The stage is an enormous bed. And what are beds for? Sleeping, dreaming, nightmares, sex…”

In other words, all the things Shakespeare’s story is about.

The fairies are worth puzzling over with their boyish stature, heavily waxed mustaches, tidy suits, bright-red gloves, and blue hair. “They’re like little butlers,” said Carsen. “The mustaches are a way of making them look a little strange. We didn’t go into science fiction, like Lord of the Rings. The idea is to dress them like servants.”

But not exactly: “We don’t want to give the public something that’s finished,” he said. “They have to figure out that [the fairy king] Oberon is invisible to everybody else on stage … it’s an element of investing yourself in the story and believing it.”

In terms of repertoire, the opera isn’t a huge leap for Opera Philadelphia — especially in light of its spring festivals, which have presented new works such as Breaking the Waves. Also, Britten’s A Midsummer Night’s Dream has been in seen in Philadelphia in two well-received student productions, at Temple University and at the Curtis Institute. Still, the opera remains difficult to peg. Knowing Britten’s most famous work, the sea-drenched music of Peter Grimes, is no preparation for the ethereal sonic cobwebs of A Midsummer Night’s Dream. The score has few traditional tunes. It acts like a chamber piece — with string glissandos suggesting forest fairies — but has grand-opera breadth. The piece was premiered in a tiny theater with roughly 300 seats. For the Academy of Music, Rovaris is using a somewhat larger 50-piece ensemble so the orchestra “doesn’t sound skinny."

“What I like about Britten is that he doesn’t show off. He serves the words, really,” said Rovaris. “If I had to relate it to another piece in the standard repertoire, it would be Verdi’s Falstaff.”

Among the singers, Rose has sung the opera a dozen times and says with iron-clad assurance that the final act is “one of the most beautiful I know.”

His anchor for the comic scenes is never trying to be funny: “The more sincerely you believe in the situation, the funnier it is.”

However, longevity — both the opera’s and the production’s — has traps that are being addressed. The high-comedy play-within-the-play that closes Britten’s Act III was a sly parody of Joan Sutherland’s 1959 breakthrough performance singing the Lucia di Lammermoor mad scene. Audiences at the 1960 premiere nearly fell out of their chairs laughing at Britten’s partner, Peter Pears, parodying Sutherland’s part in drag. Now, the scene needs updated subtext. What can flummox American ears, though, is the inflections Britten gives to Shakespeare’s words. Rose, who is British, studied Britten’s own speech on TV shows and such, analyzing how pronunciation has drifted in the years since his death at 63 in 1976, just to be sure what the composer was after.

Certain elements have evolved. The aerial beds in Act III now have seat belts — more like bed belts — thanks to greater safety awareness.

Perhaps the ultimate validation of the production is how performers keep returning to it. With opera companies casting two years in advance, Yerolemou sometimes has a devil of a time coordinating Midsummer with his theater and film commitments, which arrive more spontaneously. And yet ...

"It's a way of getting invited to a party," he says, "that you really don't belong to."

OPERA

A Midsummer Night’s Dream

Presented by Opera Philadelphia Feb. 8, 10, 15, and 17 at the Academy of Music, 240 S. Broad St. Tickets: $20-$299. Information: 215-732-8400 or operaphila.org