Grannick is something of an expert on the interplay between La Folia and cinema. In 2016, his team at Filmelodic used the variations by Francesco Geminiani, a contemporary of Corelli, as the backdrop for an experimental film. Over 12 minutes, it weaves together several stories – a ballet dancer preparing for a show, a mother accepting her daughter’s sexuality – all ebbing and flowing as the music spins from variation to variation. “The idea is that I trusted the music to make it work,” Grannick says. “In film there are certain rules of narrative arc you want to follow. But by following the dramatic arc of the music itself, I trusted that anything we did would bring the audience along.”

Critics agreed: Grannick’s film won best experimental short at the 2017 Manhattan Film Festival. Even so, the question remains. Why? Why did this humble tune, first conjured by medieval farmers, grab so many artists and never let go? Experts have their theories. John Williams, a classical guitarist from Australia, emphasises its austerity, writing on a record jacket that its simple melody means it’s “no surprise” La Folia has endured. Others are spurred by national pride. Andrés Segovia, another guitarist, called La Folia “Spanish to the core.” Silbiger feels similarly when he listens to it. “There’s a tinge of the past, of the glories of Spain,” he says. “It’s a haunting melody.”

On repeat

All good ideas, but what if they miss the point? What if the key to La Folia lies not in the score, or imperial nostalgia, but in the human mind? Elizabeth Margulis, a pianist and Professor of Music Cognition at Princeton University, thinks it could. Some years ago, she investigated a clarinet piece by Luciano Berio, a 20th-Century Italian composer. After loading the work into a digital editing programme, she artificially added repetition.

Margulis then played the original Berio and her edit to volunteers. The results were intriguing. “It turned out that people liked the [altered] excerpts more, and thought they were more interesting,” she tells BBC Culture. Not only that. “They thought the music was more likely to have been written by a human artist, rather than [being] randomly generated by a computer, if we’d inserted some kind of repetition.” In other words, artificially adding repetition can make music seem more human, not less.