TORONTO - There was a time when Leonard Cohen's "Hallelujah" wasn't even a footnote in the Montreal performer's music career.
The 1984 synth track fumbled its way into release and practically fizzled out, never being promoted as a single.
But it was gradually discovered by performers who eagerly dove into Cohen's lyrical masterpiece and eventually the covers began multiplying.
Velvet Underground founding member John Cale was one of the first to reinterpret the song and a cover by the late Jeff Buckley accelerated "Hallelujah"'s meteoric rise from obscurity.
"I couldn't think of any other song that had a trajectory anything like what happened with the phenomenon of 'Hallelujah,'" says Alan Light, author of "The Holy or the Broken: Leonard Cohen, Jeff Buckley, and the Unlikely Ascent of 'Hallelujah.'"
Light adds the song went on to develop incredible range despite its deep and dark lyrics.
"(It's) a song that people sing at funerals and they sing at weddings; that they sing in great celebration in the way he initially intended it — the opening of the Olympics — or it's very melancholy and it's very solitary and sad in the way it gets used in a lot of movies and TV shows."
It was k.d. lang who sang "Hallelujah" for the opening ceremonies of the Vancouver Olympics, while Rufus Wainwright covered it for the soundtrack to "Shrek," and the song has been featured on Christmas albums by the likes of Susan Boyle and a capella group Pentatonix.
Light has tried to find other songs that have had a similarly unusual journey: perhaps John Lennon's "Imagine," Simon & Garfunkel's "Bridge Over Troubled Water" or Sam Cooke's "A Change is Gonna Come."
He says none of them quite compare.
"There's a beautiful ambiguity in the song," Light says.
"I think it's very hard to pin down exactly what it's about."
When Steven Page was asked to perform "Hallelujah" at Jack Layton's 2011 state funeral, the former Barenaked Ladies frontman began to reflect on the themes behind Cohen's lyrics. While other covers have skipped some of the darker verses, Page preferred using all of Cohen's lyrics.
"When you perform the whole song it has a lot more rage, confusion and uncertainty," Page says.
"It's also about disappointing people. And that's a heavy topic to broach at a funeral, but I felt like it was the absolute right choice."
Others have taken the song in different directions. U2's Bono chose a trip hop-influenced spoken word approach, Wainwright brought his operatic influences, and singing contestants on shows like "American Idol" used it mostly to showcase their pipes.
"Hallelujah" also became a staple of network TV shows like "The West Wing," "The O.C." and "ER" when producers wanted to evoke a certain spiritual tone.
Vocal group the Tenors credit the song with helping define their careers.
"We've used it in many of the biggest moments we've experienced," says singer Fraser Walters, pointing to an appearance on "Oprah" where they sang it alongside Celine Dion.
"We've taken that song across the world."
Walters credits Cohen's astute lyrical ability for giving "Hallelujah" a nuance that let it be reinterpreted countless times over.
"That's the sign of a great songwriter," he says.
"Even though there might be some personal messages in there for Leonard himself, people were able to make it their own. The melody is so hauntingly beautiful, I would say it's almost like a mantra."
Cohen once expressed mild exasperation with its newfound popularity.
"I think it's a good song, but I think too many people sing it," he told the CBC in 2009.
Page says he agrees that performing "Hallelujah" has become a bit of a cliche.
"At the end of the day, those cliches happen because they affect people over and over again," Page says.
"They get punched in a gut by something in a song and can't even articulate it. That's what great songs do, they articulate a feeling for us."