Blake Sell / Reuters

Before it was one of the best-selling singles of all time and an Oscar-winning flashpoint in an eternal cultural battle over schmaltz, “My Heart Will Go On” was a secret. During Titanic’s filming, its director, James Cameron, “was opposed to composer James Horner’s desire for a closing pop ballad, thinking it at odds with the score’s attempt at period authenticity,” wrote Carl Wilson for The Atlantic in 2012. “So Horner pursued it behind Cameron’s back. He solicited lyrics from his friend Will Jennings, and set his sights on [Celine] Dion. She hated the song at first herself, but her husband/manager Rene Angelil persuaded her to sing on the demo (literally weeping while doing it, by some accounts), which in turn convinced Cameron.”

Horner, who died at age 61 on Monday in a plane crash, was among the most prolific name-brand composers working in Hollywood, racking up 10 Oscar nominations and dozens of huge film credits—Braveheart, Apollo 13, Field of Dreams, Aliens, and Avatar among them. But Titanic, the second-most popular film score of all time, stands somewhat above the rest in terms of its cultural impact and awareness, for better and for worse. The “worse” part probably needs no explanation: Both film and music experienced waves of critical and popular backlash for their overt sentimentality. “Teen-age Titanic fans may not swoon for long to this music once they’ve taken it home,” wrote Alex Ross, The New Yorker’s classical-music critic, in March 1998. “Horner, who studied at the Royal College of Music and then graduated to Roger Corman’s B-movie shop, is set to become the biggest phenomenon in the history of used-CD stores.”

The stats on the album’s performance in second-hand record stores weren’t immediately available. But what’s clear is that Titanic’s music hasn’t faded from the popular consciousness in the nearly 20 years since the film’s release, not really. It’s been reissued and rerecorded a number of times. A worldwide tour in which it’s performed live by an orchestra is currently snaking through Europe. And “My Heart Will Go On” sits as the 11th best-selling single of all time, and still gets covered by punk bands, Disney stars, and karaoke warblers. The music’s commercial success may well owe to the over-the-topness that so many people find off-putting about it, a dynamic that speaks to the challenge facing all film composers. Do you serve the screen, or do you serve the music? Do you play the expected and timelessly compelling, or do you challenge filmgoers with the kind of musical accompaniment they hadn’t heard before? Do you hit them in the gut, or the mind?

For the most part, Horner answered the above questions with “both.” Hans Zimmer’s brooding bombast or John Williams’s grand melodies weren’t his style; his scores tended to be more delicate things, rummaging through musical history and diverse cultures while also providing plaintive, pop payoffs. Ross described the “New Age Celtic sound, with cooing pipes and electronic choirs” of some of Horner’s ‘90s output as being incongruous for Titanic’s subject matter, but that’s part of what made it so striking—the way it keyed into the story’s emotions using sounds that weren’t quite expected. He could create strange, otherworldly atmospheres—check the atonal skittering and chimes of the “if you build it” scene in Field of Dreams, or the early tracks for Aliens—but they always gave way to satisfying crescendos.

His work on Avatar is perhaps the purest distillation of his varying impulses, requiring him to a conjure never-before-heard sounds for what at its core was a classic adventure story. Speaking to The Los Angeles Times in 2009, Horner said he digitally manipulated a variety of indigenous instruments to make them sound “alien” and yet “warm.” In that same interview, he talked about his long relationship with James Cameron. “He and I get into tussles sometimes when I think something should be a little bit more human or heartfelt and he thinks it’s not necessary,” he said. “I’ll write a cue two different ways just to cover myself. Sometimes he will use the drier way and then, a month later, he’ll swap out the cue for the version I proposed in the first place.”

It’s a fascinating anecdote—one that gets at his faith in the emotional, the same faith that led him to create “My Heart Will Go On” without Cameron’s approval. Regardless of one’s opinions of the song, it’s a cultural landmark; Wilson’s Atlantic article proposed that it may be destined to become a folk standard. Horner probably didn’t have that fate in mind, of course—as befits someone who was scoring multiple films a year, he was just trying to do his job. Last year, he sat down for an interview with David Hocquet of the insanely detailed fan site James Horner Film Music. “Your music will live on in our minds and in our hearts, and apart from the film,” Hocquet told him. Replied Horner: “I mean it's nice to be reminded and I'm very flattered, but I just lose track of all of that. I do my best and then I put it in the mail and hope for the best.”

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.