Kenny Gamble and Leon Huff let the scale of their ambitions be known in 1971 with the middle name of their new label, Philadelphia International Records. As the O’Jays would sing the next year on “Love Train,” PIR and the Sound of Philadelphia were meant for “people all over the world.”

Fifty years later, Philadelphia and the world are poised to celebrate the golden anniversary of the label that was home to Harold Melvin & the Blue Notes, Patti LaBelle, Teddy Pendergrass, Billy Paul, The Intruders, McFadden & Whitehead, and more.

Deluxe CD and LP box sets are scheduled to roll out over the course of 2021, organizers announced Monday. A Gamble-hosted Sound of Philadelphia channel will launch on the Sonos music platform in February. Black Music month in June will bring a focus on the women of Philadelphia International, including Phyllis Hyman, the Jones Girls, and Three Degrees.

The flurry of projects is intended to elevate the Philly International brand and to accord Gamble and Huff — along with key collaborators like their “Mighty Three” songwriting partner Thom Bell — increased respect as 20th-century Black music creators on a par with titans like Motown’s Berry Gordy.

>> WATCH: In a 1991 interview, Gamble and Huff talk about the Philadelphia Sound

The re-release train starts in April, when British label Snapper Music will put out the first of four lushly packaged, limited-edition eight-CD boxes planned for 2021 — the start of an epic project to reissue the PIR catalog in its entirety.

The first box, Get on the Soul Train, is a nod to “TSOP (The Sound of Philadelphia),” the theme song for TV’s Soul Train. Gamble and Huff wrote that hit for the PIR house band MFSB featuring the Three Degrees.

The Soul Train set features remastered recordings of classic albums by The O’Jays, Billy Paul, and The Intruders, along with less well-remembered artists like Hawaiian singer Dick Jensen. It will also include a 64-page hardcover book.

A second box, Satisfaction Guaranteed, will come out in June. Two more, Love Is The Message and I Love Music, are due out later this year.

In total, Snapper plans to issue 15 eight-disc boxes in the coming years devoted exclusively to PIR. Each set will by limited to 2,500 copies.

Beyond that, the music club Vinyl Me, Please will release this summer an eight-record set called Anthology: The Story of Philadelphia International. Both the Snapper boxes and the Vinyl Me LPs are being released in conjunction with Legacy Recordings, the catalog division of Sony Music.

The makers behind the music

The list of Gamble and Huff hits is voluminous, from Harold Melvin & the Blue Notes’ “If You Don’t Know By Now” in 1972 to the Three Degrees’ “When Will I See You Again” in 1974 to Thelma Houston’s “Don’t Leave Me This Way” in 1976. There are too many to count.

The duo did most of their songwriting, Huff recalls, in Gamble’s office in the PIR offices at 309 S. Broad St., which had previously housed the Cameo Parkway record label.

“I worked at the upright piano,” says Huff, now 78. “Gamble would be sitting beside me with the tape recorder running all the while. Gamble was a great singer, and he could sing in the style of whoever we were writing for.”

While music lovers know the songs, they may not appreciate the full backstory. The goal of the 50th anniversary campaign is to let people know that “Gamble and Huff were behind the music,” says Chuck Gamble, Kenny’s nephew, who manages the duo and is an executive with their publishing company, Warner Chappell Music.

“That’s number one,” he says. “And then to show people the sound that specifically came out of Philadelphia, and how it was created.” That sound was uniquely rugged and sophisticated, with string players from the Philadelphia Orchestra often joining members of the MFSB house band to record PIR hits in Joe Tarsia’s Sigma Sound Studios on North 12th Street.

Beyond that, Chuck Gamble says, “we want to show how it was a struggle for African American men to get where they got to,” he says, “and what it took to get to that plateau of success, as writers, producers, and executives.”

‘This was the way the world was’

The Gamble and Huff alliance began in 1963, when the two hardworking musicians from West Philly and Camden met in the elevator of the Shubert Building, which now houses the Merriam Theater and at the time was full of upstart music companies.

“There were hundreds of independent producers and writers in Philadelphia then,” recalls Gamble, now 77. “There was a tremendous music industry, because of Dick Clark and American Bandstand.

That didn’t make things easy, though. “If Dick Clark would play your record on Bandstand, you would have a No. 1 record all over the country in three days,” Gamble says. But Bandstand would rather play Pat Boone’s version of “Good Golly Miss Molly” than Little Richard’s. That was the way the world was. So you have to just grin and bear it, and keep doing your best.”

When he met Huff, “It was like a miracle,” says Gamble. “Because we both had the same dreams.”

Huff grew up playing gospel music. “But I wanted to rock like Little Richard,” he says. Before he came together with Gamble, he’d had steady work as a session pianist in New York, playing on the Ronettes’ “Baby, I Love You” and the Phil Spector-produced classic holiday album A Christmas Gift For You.

Gamble led a group called Kenny & the Romeos that was the house band at Loretta’s Hi-Hat in Lawnside. “I wanted to get in that band so bad,” Huff says. He did when the piano player — Thom Bell — left to take a job at Cameo Parkway, the home to teen idols like Frankie Avalon and Bobby Rydell.

“Philadelphia was a center for pop music,” says Gamble. “It was really a great era. We wanted to do the same thing, but do it for African American culture.”

Hit songs, then a deal with Clive Davis

The first song that Gamble and Huff worked on together was “The 81,” a 1964 tune that Gamble wrote with Jerry Ross, featuring Huff on piano. The duo then had success with the Soul Survivors’ “Expressway To Your Heart” in 1967 and The Intruders’ “Cowboy to Girls” in 1968. The music came out on a variety of indie labels.

“You’ve got to struggle sometimes,” Gamble says. “That’s why we wrote songs like “Only the Strong Survive,” for Jerry Butler. You know, Elvis Presley recorded that song? The story is that he would walk around his house singing “Only the Strong Survive,” and one of his producers said, ‘Let’s record it.’”

With Motown as a model and inspiration, Gamble and Huff signed a deal with legendary record man Clive Davis, then head of CBS Records, to create Philadelphia International in 1971.

The first album released was Going East by Billy Paul, the jazzy soul singer who would explode the next year with his sublime sneakin’ around song “Me & Mrs. Jones,” penned by Gamble and Huff with Cary Gilbert.

The CBS deal was an instant success. “Gamble and Huff blew up,” Davis wrote in his memoir, Clive: Inside the Music Business. “Within nine months they sold 10 million records.”

CBS took care of distribution worldwide. “It was hard for young African American producers and songwriters. That was just the way the industry was. Two guys from Philly, it was kind of hard for us to distribute our work,” Gamble says. “The deal took a lot of weight off our shoulders.”

PIR forever

The persistence of radio staples like the O’Jays’ “Backstabbers” underscores PIR’s continued place in pop culture, and their catalog has been widely repurposed in hip-hop and used in commercials.

One case in point: “(You) Got What I Need,” a song that Gamble and Huff wrote and produced for Freddie Scott in 1968.

Biz Markie used it as the basis for his 1989 hit “Just A Friend.” Kanye West sampled it on “Good Friday” in 2010. Janelle Monáe sang it in a Gap ad in 2017. And this past holiday season, it was featured in an Etsy TV commercial.

Huff says Philly International’s longevity boils down to “the songs we wrote — ‘Love Train,’ ‘Wake Up Everybody,’ ‘Family Reunion’ — they’re still relevant. ‘For the Love of Money.’ I hear those songs now, and they still sound as good today as when we recorded them.”

Gamble spreads the credit around. “We had a great team of producers, engineers, and writers. We had artists who can sing. A great band. Everybody had the same goals and objectives. And when you think of Thom Bell and “Didn’t I (Blow Your Mind This Time),” and the strings and the oboes … We brought instruments into rhythm-and-blues that people had never heard before.”

He can’t name a favorite moment from an era when everyone from the Jacksons to B.B. King to David Bowie came to Philadelphia seeking Philly soul magic.

“My favorite thing is that it happened,” Gamble says. “Sometimes I think about it, you know, and it feels good. It feels good that we were able to come together and write songs from the heart — and that people all over the world took to those songs.”