A few years ago, as pop superstar and former One Direction member Harry Styles was in the midst of recording his sophomore album, Fine Line, he went to Culver City on a mission. "I am a Joni Mitchell fan," Styles told the person he was seeking out in California over the phone, "and I researched and found you — do you have any dulcimers for sale?"

That person Styles tracked down was Joellen Lapidus, the woman who sold Mitchell her first dulcimer — a long, stringed instrument that was once used by Tibetan monks as well as musicians entertaining Persian royalty. In modern history, it is maybe most commonly associated with Mitchell and her fourth album, Blue. It's the album Styles became obsessed with while writing his 2019 record, and if you listen closely, the dulcimer is featured on the Fine Line cut "Canyon Moon," which he described to Rolling Stone as "Crosby, Stills and Nash on steroids." (Some of the songs off Blue are famously inspired by Mitchell's relationship with Graham Nash.)

Styles is not the only artist to have gone on this Mitchell pilgrimage, both literally and metaphorically. Fifty years after its release, Blue remains one of the most influential albums in music history, and it continues to find its way to the ears of young musicians, including Carly Rae Jepsen, Taylor Swift and Brandi Carlile, who have all name-checked the Canadian icon and her seminal work as inspirations. It is perhaps one of the most definitive breakup albums of our time, a masterclass in vulnerability and honesty all wrapped up in a pop album that laid Mitchell's feelings bare. As she once described it:

"I felt like a cellophane wrapper on a pack of cigarettes. I felt like I had absolutely no secrets from the world, and I wouldn't pretend in my life to be strong. Or to be happy. But the advantage of it in the music was that there were no defences there either."

Blue is also the album that served as many people's introduction to the dulcimer, one of Mitchell's not-so-secret weapons on the album. It is the first sound you hear on opener "All I Want," and it reappears throughout on "Carey," "California" and "A Case of You." A beautiful, saccharine sound, the dulcimer can often emulate something like a guitar or banjo, and falls into the zither class of stringed instruments. Lapidus, a fan of Mitchell's, set off for the 1969 Big Sur Folk Festival to try and sell the Canadian songwriter one of her dulcimers, and succeeded, selling her one of her custom models for $200.

One of the lines Lapidus used to sell Mitchell the instrument was telling her, "You know, this is something that you could really get into because it's all opening tuning." Mitchell's experiments with tuning — using upwards of 50 different tunings — throughout her career was something that many admired, as Buffy Sainte-Marie told CBC Music: "[Joni] wasn't afraid to use alternate tunings. I was pretty lonesome until Joni came along." With a dulcimer, Mitchell was able to continue exploring, often drawing from her experiences playing the guitar in altered tunings. (When Lapidus sold Mitchell that dulcimer, Lapidus taught Mitchell some strumming techniques, which were derived from her skills as a folk guitarist.)

The dulcimer is said to have originated from German immigrants who brought their instrument, the German scheitholt, with them to the U.S. From there, the scheitholt was placed on a larger sound box and its nine strings narrowed down to just three to five. Over the years, makers have tried different shapes, sound-hole patterns and strings, with regional models coming out of Kentucky, West Virginia and the Appalachian Mountains. The instrument's name comes from a Greek word meaning "sweet song."

It's quite fitting then that Mitchell left California and wrote most of Blue in Europe, including Greece, where she met the inspiration behind "Carey," a local cook named Cary Raditz. All Mitchell had with her was a flute and her dulcimer because they were light and compact, and Mitchell later sent Lapidus a postcard from Crete, telling her how much she loved her dulcimer.

On Blue, the dulcimer almost counteracts the album's sadness. Its feathery strums are woven into guitar riffs, its understated presence in the background never overtaking Mitchell's soaring voice and poignant songwriting. But it structurally keeps the tracks on Blue elevated, like fluttering wings lifting Mitchell's spirits even in dark moments. While Mitchell's words do the heavy lifting, the dulcimer adds a note of hope, a sliver of sunlight peeking through the clouds. That love Mitchell has for the instrument, that she wrote to Lapidus about, is evident in every second of those four songs.

Mitchell is, of course, not the first or last artist to popularize or use this instrument. Jean Ritchie inspired the works of Mitchell as well as Bob Dylan and Shirley Collins; in 1966, Brian Jones played the dulcimer on the Rolling Stones' album Aftermath; and Jeff Buckley played the dulcimer on "Dream Brother," the closing number on his 1994 album, Grace. But no one truly embodied the history and the potential of the dulcimer quite like Mitchell, and while that isn't the biggest or most important takeaway from Blue, it's perhaps one of the biggest reasons why dulcimers are still sought out today — sometimes by ordinary Mitchell fans, sometimes by world-renowned pop stars.