When Iranian virtuoso Kayhan Kalhor performs Friday at Walker Art Center alongside the American chamber quartet Brooklyn Rider, the finale will be a sprawling epic titled "Silent City."

Composed by Kalhor to commemorate the people killed during Saddam Hussein's chemical gas attack on the Iranian-Kurdish city of Halabja in 1988, the nearly 30-minute piece begins shrouded in desolation. The ethereal atmosphere slowly fills with echoes and rhythmic loops, spotlighting the haunting beauty Kalhor derives from the kamancheh, a four-stringed upright fiddle common in Persian classical music.

"Silent City" has become a contemporary classic, developed with members of Brooklyn Rider as well as renowned cellist Yo-Yo Ma as part of a Harvard program back in 2005. But their shared history extends even farther back, to a gathering of musicians at Tanglewood in Massachusetts in 2000 that led to Ma's Silkroad Ensemble.

"The world Kayhan was coming from was brand new territory for us," said violist Nicholas Cords, the White Bear Lake native who is a Silkroad member alongside Kalhor and Brooklyn Rider bandmate Colin Jacobsen. "But on the other hand it felt like he was a kindred spirit, or a distant ancestor, in the way that our instruments related."

Shortly after their reunion at Harvard, Cords and Jacobsen visited Kalhor in Iran to become further enmeshed in the music and culture of his heritage. "Kayhan is one of the reasons Colin rekindled his passion for composing," Cords said.

Two pieces by violinist Jacobsen will begin Friday's concert. One, "Atashgah," was inspired by an ancient temple they visited in Iran. The other, "Beloved, Do Not Let Me Be Discouraged," appears on the collaborative album "Silent City," released in 2008.

"Meeting Kayhan was an important part of how we came to define ourselves as a quartet," Cords said of Brooklyn Rider. "We knew that any collaborations had to be a peak experience of getting into each other's traditions, building a friendship, and letting it flower over many years."

A kamancheh prodigy who was playing in Iran's National Orchestra by age 13, Kalhor is globally renowned as a master of Persian music in its many forms, an in-demand solo virtuoso, and an open-hearted collaborator.

He has known strife and tragedy. At 17, he walked nearly 2,500 miles to Italy after the Iranian Revolution broke out, carrying only a small backpack and his kamancheh. Four years later, his parents and brother were killed in a missile strike during the Iran-Iraq War. Kalhor eventually settled in the United States, but felt compelled to leave in 2002 due to anti-Muslim sentiments in the wake of the Sept. 11 attacks.

That background adds weight and resonance to his comments in a recent phone call from Tehran. Told of Cords' comments about being kindred spirits and distant ancestors due to the lineage of their instruments, he talked of how different countries used lambskin or snakeskin as the hide covering their bowed instruments, and gourds or coconuts for the body.

"Like the family of instruments, we humans are all related, whether we like it or not," he said, chuckling. "We are all the same people, coming from the same place.

"When Colin and Nick visited Iran, they were amazed by the music and culture and wanted to learn it. That process helps us become better musicians and better humans. The more people and places you know, you can make a more colorful painting. It just helps you have a larger vision of the world."

At the midpoint of Friday's concert, Kalhor will perform a spontaneous solo. It will be much abbreviated from his traditional solo improvisations, he said. "In my culture you build something; you have this architecture where if people listen for an hour or more, they can travel with you and understand what you are doing on the journey."

Yet Cords promises that even this abbreviated 15 minutes or so will be an adventure. "Kalhor invents a completely different world when he plays. From the first note it feels timeless. He gets in a zone that has both this incredible sense of freedom and this elaborate structure he is creating step by step."

Then it will be time for "Silent City." The first half of the composition is almost entirely improvised, then yields to a stirring, fully annotated climax of lyrical consonance from the strings, another quieter period, and a closing dance passage and the city comes back to life.

Although Kalhor has performed the piece since the isolation of the pandemic, this is the first time he and Brooklyn Rider have been able to renew their once-annual concerts together.

"A silent city bringing itself to new life gradually over time," Cords mused. "I think those of us onstage and in the audience will know a little better exactly what that feels like."

Kayhan Kalhor & Brooklyn Rider
When: 8 p.m. Friday, Oct. 29
Where: Walker Art Center, 725 Vineland Pl., Mpls.
Tickets: $35.50. walkerart.org or 612-375-7600

Britt Robson is a Minneapolis freelance writer.