The Coen Brothers' 2000 tragicomedy O Brother, Where Art Thou?, set in Mississippi during the Great Depression, pulls deeply from the early-20th century American songbook to drive the film's Homeric storyline, which entangles the lives of escaped convicts Delmar O'Donnell (Tim Blake Nelson), Pete Hogwallop (John Turturro) and Ulysses Everett McGill (George Clooney).

But while nearly all 19 tracks on the original soundtrack, released December 5, 2000, are once-popular songs enshrined in the Library of Congress, the music wasn't designed to be a hit outside the world of the Soggy Bottom Boys, the film's fictional band composed of the main characters. "Old-Time Music is Very Much Alive!" trumpets the faux Nashville Banner headline in the liner notes to the film's original soundtrack, "But you won't hear it on 'country' radio." 

The prophecy proved true. The popularity of O Brother, Where Art Thou? didn't help traditional music break into radio programmers' playlists—the single for "I Am A Man Of Constant Sorrow" peaked at No. 35 on the Billboard Hot Country Songs chart—but it didn't matter. The soundtrack sold more than 8 million copies in the U.S., certified eight times platinum, and won Album Of The Year at the 44th GRAMMY Awards.

On that February evening in 2002, bluegrass legend Ralph Stanley stunned the audience at the Staples Center in Los Angeles with an a cappella performance of "O Death," a traditional folk song featured on the soundtrack, delivered by the then-73-year-old under a single spotlight in the middle of the darkened arena. (Stanley went on to win the Best Male Country Vocal Performance GRAMMY for the track that night.)

"Having Ralph Stanley stand on a stool in the middle of the room and sing 'O Death' was the pinnacle of my entire career," Luke Lewis, whose Lost Highway label released the soundtrack and who also led the Nashville operations of Mercury, MCA and UMG at various points, tells GRAMMY.com. "I was sitting with a bunch of f*cking gangster rappers who were completely blown away."

But the odyssey began long before a host of country, gospel and bluegrass ringers upturned the industry on music's biggest night—before the Coen Brothers even began filming, in fact.

In the spring of 1999, producer T Bone Burnett convened at Sound Emporium in Nashville with a who's who of roots musicians from the city's vibrant bluegrass scene, including Gillian Welch and Alison Krauss & Union Station, to put the song cycle to tape. Lewis, who was just beginning to assemble Lost Highway Records as a creative haven for roots artists like Lucinda Williams, caught wind of the sessions and went to investigate.

"I walked into that creative process when all that was going on, and the Coen Brothers are hanging, T Bone's in there," Lewis recalls. "All these amazing artists come in there and do the record old school, with a mic in the middle of the room."

Classics such as "I'll Fly Away," "You Are My Sunshine" and "In The Jailhouse Now"—the latter sung by actor Tim Blake Nelson—are rendered slower and lower than typical bluegrass interpretations. That was an intentional move, Burnett says, to capitalize on the bass response of the subwoofer-loaded sound systems in movie theaters.

"The first thing we did was stretch the sonic spectrum that bluegrass was ordinarily recorded in, which was very high—the banjo was high, the singing was high, the violins were high, the mandolins were high—and we lowered it a couple of octaves and approached it more as a rock 'n' roll album rather than a traditional bluegrass record."

While Krauss took lead vocals on "Down To The River To Pray," elsewhere collaborating with Welch and Emmylou Harris on "Didn't Leave Nobody But The Baby," her Union Station guitarist Dan Tyminski was asked to audition for the cut of a lifetime: singing lead on "I Am A Man Of Constant Sorrow," the hit Soggy Bottom Boys song "sung" by George Clooney in the film. 

"I was happy to do it, but I honestly didn't feel like it made a lot of sense," Tyminski remembers. "I didn't necessarily see myself sounding like Clooney's voice at the time, but it's hard to see from your own perspective what other people see or hear. So, I went back and auditioned the next day, and somehow [I] got it, and just couldn't have been more shocked at what would follow."

Read: 'O Brother, Where Art Thou?' Soundtrack | For The Record

The brains behind the soundtrack were just as surprised when the film opened in France, prior to its stateside debut, and sold 70,000 copies of the album within a month. It was a hint of what was to come in the U.S. 

As the film's signature song, "I Am A Man Of Constant Sorrow" helped drive the soundtrack to the No. 1 spot on the Billboard 200, where it spent 15 weeks during a 683-week run on the chart.

The song became Tyminski's calling card, but he almost didn't get to play it. After his version was done and filming had begun, Clooney himself asked to take a pass at the vocal. Tyminski went back to the studio on a day off from shooting and backed him on guitar.

"George is actually a really great singer and had learned the song well, and he sang a killer version of it," Burnett says. "But it didn't have the thrill in it that Dan's version had. And so I just said, 'This is great, but we're supposed to be making a movie about a hit record, and now we've got something that sounds like a hit record, so I think we should stick with that. What do you think?' And I think he was relieved, really."

Tyminski says the recording process also played a role in the decision to use his version. "It's not that he couldn't do the job," he says, "but for the sake of the movie, it had to be one take, live, no fixes. It was all really pure, all very organic. 

"After he had taken a couple of swings at it and got the words jumbled a couple of times, he says, 'Dan, I'll make you a deal: I'll act, you sing.' And quite honestly, I was so disappointed because I thought it was so cool to have recorded the song with Clooney. At the time, it felt like that was a bigger deal than singing the song myself. It wasn't until a little bit later that I realized what a loss that would have been. It ended up being the biggest song of my career, easily."

Read: Exclusive: Gillian Welch On Vinyl, Songwriting, 'O Brother...' & More

Tracking down the writers of songs composed nearly a century earlier proved to be an enormous job for Burnett and Denise Stiff, who managed Welch and Union Station. The songs were recorded and re-recorded over the decades, and many versions were unique enough to support their own copyrights. That meant when Burnett used or rewrote an arrangement, they had to determine which previous version of the song was closest and credit the right people. 

"'Man Of Constant Sorrow' has, I think, 50 copyrights in the Library Of Congress," Burnett says. "The one we worked with most closely was The Stanley Brothers' version. Even though we had done our own arrangement, we could've gotten sued by 50 people for infringement."

The version of "I Am A Man Of Constant Sorrow" recorded for the film earned Tyminski a GRAMMY for Best Country Collaboration With Vocals at the 2002 GRAMMYs. In addition to the Album Of The Year win, the soundtrack also won for Best Compilation Soundtrack Album For A Motion Picture, Television Or Other Visual Media, while T Bone Burnett won for Producer Of The Year, Non-Classical.

Two decades later, it's hard to say what lasting impact the success of O Brother, Where Art Thou? made on contemporary country music, or popular music in general. The widespread acclaim for the film and soundtrack is undeniable, and they both made gobs of money. But it could be argued—and Burnett does—that a revival of roots music was already underway when it all hit. 

"The reason I think it was so successful [was] because, one, there was already a very strong traditional music trend," Burnett says. "Kids were learning how to do it."

So-called "alt-country" bands like Wilco and Old 97's were impacting the lower rungs of industry charts, along with Jayhawks, Whiskeytown and others. Bluegrass trio Nickel Creek had hooked up with Krauss and released their 2000 self-titled, platinum-selling album, while bluegrass-adjacent bands Old Crow Medicine Show and The Avett Brothers were beginning to make names for themselves on the touring circuit. 

"Certainly, country radio didn't change, and you wish for things like that to happen," Lost Highway founder Lewis says. "But it makes you aware that there's a wider world than what you hear on mainstream radio, and for a lot of people who really love music, you need something to lead you down the path because it's hard to find guideposts to things you might like. I think O Brother had that sort of impact."

There's another reason, too, Burnett suggests. On the night of the 2002 GRAMMYs, Americans were still reeling from the September 11 terrorist attacks that took place just five months earlier. Tony Bennett and Billy Joel sang a duet on "New York State Of Mind," a nod to the resilience of the city amid tragedy. Alan Jackson performed "Where Were You (When The World Stopped Turning)" in front of children's art created in reaction to the attacks in New York, Washington, D.C., and Pennsylvania. And in the middle of it all, Ralph Stanley stood on the GRAMMY stage, alone and vulnerable, pleading with his maker, "Won't you spare me over for another year?"

"Art responds to events without the artists meaning to at all," Burnett says. "The Beatles weren't responding to Kennedy's assassination, and yet everything about The Beatles felt like the thing that we needed the most after the Kennedy assassination. People were looking for our identity as Americans. Why did we get hit like this? Who were we?"

While the music of O Brother, Where Art Thou? offered millions of Americans the comfort of nostalgia, it impacted others in more material ways.

"It did amazing things for the artists that were involved," Lewis says. "All of a sudden, they were going on the road and making 10 times what they made before the record came out. They got royalty payments that they probably didn't ever dream of."

Mississippi-born singer James Carter had forgotten about the day in September 1959 when Alan Lomax recorded him singing "Po Lazarus" at the Mississippi State Penitentiary at Parchman until producers tracked him down in Chicago to present him with a platinum record plaque and a $20,000 royalty check for his performance. The 76-year-old former convict even attended the GRAMMY Awards that night, though he could barely remember recording the song.

In the years that followed, Tyminski recalls that the demographics of Union Station shows began to swing younger than before: more rock T-shirts, more spiked haircuts. He also remembers the rousing applause for the song that George Clooney, as Ulysses Everett McGill, sang into a can in the film's pivotal recording scene.

"From that point forward, that song was in every single show that we did," Tyminski says. "But when you have a song that's been that good to you and that people identify with and they want to hear, shame on you if you're not willing to play that song for the rest of your life."

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