Even though the Armenian genocide depicted in Open Road's The Promise took place more than 100 years ago, when Chris Cornell wrote the searing end-title theme, he wanted to bring awareness to similar atrocities going on today.

"Rather than people thinking, 'Wow, what a horrendous thing that happened a century ago,' I'd love for them to realize that it is happening now and the fact that the warning signs are always the same leading up to a genocide," said the late Soundgarden singer in an interview a few weeks before his May 2017 death and shortly before the film, starring Christian Bale and Oscar Isaac, opened.

However, when Cornell wrote "The Promise," musically he stayed rooted in the past. "That was a conundrum I hadn't dealt with before. I couldn't have any popular music references that are natural to me" like Led Zeppelin or The Beatles, he said. He also didn't want to write a strictly period piece tied to the early 1900s, using only instruments that existed in Armenia, "because the song needed to do a bigger job, it shouldn't be confined by geography or time." He settled on acoustic guitar, piano, tympanis and strings, with orchestration by the late Grammy-winning arranger Paul Buckmaster.

Lyrically, Cornell, who earned a Golden Globe nomination in 2012 for "The Keeper" from Machine Gun Preacher, drew from The Promise writer-director Terry George's script and rough edits of the film, as well as research — reading and watching documentaries — about the genocide. He told the story from the perspective of a young man singing to a photo of his father or grandfather about the inspiration they had provided by persevering through horrendous acts. Though not Armenian, Cornell also drew upon his wife's Greek heritage since her ancestors were affected by the same World War I genocide that led to the death of 1.5 million Armenians.

Cornell, who donated proceeds from the song to the International Rescue Committee, an organization that provides assistance to those fleeing conflict, wanted to leave viewers with a sense of hope. "The hope was built into the story," he said. "To me, the challenge was being able to distill it in a couple of verses and a chorus.

This story first appeared in a November stand-alone issue of The Hollywood Reporter magazine. To receive the magazine, click here to subscribe.