In the mid-1980s, Disney’s animation arm was at a low ebb, cranking out titles like “The Black Cauldron” and “The Great Mouse Detective” — a far cry from the glory days of “Snow White and the Seven Dwarfs,” “Pinocchio” and “Bambi.”

Then songwriters Alan Menken and Howard Ashman arrived on the scene. Their work on “The Little Mermaid,” “Beauty and the Beast” and “Aladdin” ushered in a new era at the studio.

“?’The Little Mermaid’ not only reinvigorated Disney animation, it virtually reinvented it using the template of the Broadway musical,” says historian Leonard Maltin (author of “The Disney Films”), adding that “it had been many years since songs from a Disney movie had real life outside of the movies themselves. Their music was also a big reason that grownups responded to the films as well. This was not kiddie music.”

Ashman died in 1991. Menken completed “Aladdin” with Tim Rice and went on to further success with “Pocahontas,” “The Hunchback of Notre Dame” and other animated musicals, in partnership with other lyricists. All of Menken’s eight Oscars (four for best song, four for original score) are for Disney projects. In 2007, he received three more Oscar nominations for his songs for the live-action/animation combo “Enchanted.”

Now, the composer is back with his 10th Disney musical, “Tangled” (based on the fairy tale “Rapunzel”). “Tangled” also happens to be the studio’s 50th animated feature and, says Menken, it posed the biggest creative challenge to date — in part because Pixar personnel are now in charge at Disney and the sensibility has changed.

“Finding a way that we could wed musical-theater storytelling with the Pixar style of storytelling was primary,” he says. “How much of a fairy tale will it be? How much will we keep it contemporary? How much of a break-into-song can it be? Do we want to harken back to traditional Disney, or break with it?”

Menken, his lyricist Glenn Slater and the “Tangled” team struggled with the approach during the entire 2 1/2 years that Menken was on the project.

“Every project has its own trunk,” Menken says, using the old Tin Pan Alley term for songs written and then discarded. “?’Tangled’ has a trunk and a half.”

Most of the five Menken-Slater songs that survived the process are tinged with a folk-rock sound that initially inspired the composer. “It was (an area) that I always wanted to work in,” he says. “I thought about Joni Mitchell, Cat Stevens, all that great American and English folk rock. That was the starting point.”

The “long hair” connection between ’70s folk rockers and Rapunzel’s legendary tresses was part of that inspiration, he admits, along with the concept of “yearning for freedom,” as the teenaged girl is imprisoned in a tower by a woman she thinks is her mother. (Mandy Moore does the voice of Rapunzel, while Broadway vet Donna Murphy chews up the animated scenery as her evil faux mom.)

“Tangled” met Menken’s criteria for tackling any new project: “I can imagine the story being told through songs, and through a musical vocabulary that is fresh and original, where I haven’t been before,” he says.

That’s been a hallmark of Menken’s music since he started with Disney on “The Little Mermaid,” which opens with sailors singing an authentic-sounding sea shanty. “In every musical, from the very top, you need to say, ‘these are the rules of the game, this is the world you’re in,’?” he says. “Having this ship come out of the mist, to a sea shanty, tells you so many things: It tells you it’s mythic, it’s a fairy tale and it’s musical theater. And it revels in it.”

“Mermaid’s” “Under the Sea” was a Caribbean-style calypso that wound up winning an Oscar. And while the title song for “Beauty and the Beast” won Menken his next Oscar, it’s the can-can “Be Our Guest” – — led by the French candlestick Lumiere — that was the film’s showstopper. “Aladdin” is filled with mystical Arabian-nights colors, “Pocahontas” with Native American flutes and percussion, “Hunchback” with medieval choral sounds and gypsy violins.

But Menken’s success at Disney all stems back to his 12-year collaboration with Ashman. “The Little Mermaid” followed their work on “Little Shop of Horrors,” a 1982 off-Broadway show that became a 1986 film that also earned them their first Oscar noms.

“So we brought a great deal of confidence to the task,” Menken recalls. “And we also brought a real faith in musical theater — and the ability of musical theater to enchant people. We were unapologetic about our musical-theater influences, and I think that’s what people embraced.”

Adds Chris Montan, president of Walt Disney Music: “Alan and Howard taught the movies to sing. ‘Little Mermaid’ was such a huge jump, and for the next 10 or 12 years we had a number of hits that featured humor, heart and great music. They were really responsible for a whole renaissance in Disney animation.”

‘Tangled’ up in cues | Broadway a perilous ‘Leap’ | Pitch-perfect partner