Estonia's budding independence drive in the 1980s was dubbed the Singing Revolution for the massive and peaceful rallies when crowds often sang in old-form, chanting styles popularized by Tormis.
Tormis' haunting yet beautiful a cappella compositions typically incorporated a chanting, runic style that conjured up images of shamans and now-forgotten ancient peoples along the Baltic Sea shores.
His works garnered international acclaim after Estonia regained independence in 1991, with choirs from Korea to the United States performing his music.
Tormis' best known and most performed work, "Curse Upon Iron," became an unexpected staple in an unexpected place: The Oregon City High School in suburban Portland. Amy Aamodt, the school choir director at the time, explained how the choir first took on the difficult piece around 2010 with hesitancy as they sang in the original Estonian - but then quickly became enthralled.
"Even when we were learning his music, I would look up and there would be tears in the kids' eyes. ... Something just clicked about his music," an emotional Aamodt said in a phone interview Monday after learning from a reporter about the composer's death. "The piece was so much deeper than any of us could have imagined."
"Curse Upon Iron" is an ode to the horrors of war written for choir and hoop drum in which singers are instructed in the score to spin, crouch and shriek at points, adding to its power. The Estonian lyrics speak of the curse of war and its weapons: "Wretched iron! ... You flesh eater, gnawer of bones!"
The effect when the student choir performed the work, even though the words were foreign to everyone in the audience, was universal, recalled Aamodt.
"I would look out - and the parents were crying," she said.
Soft-spoken and modest, Tormis described his compositions as keeping alive the memories of ancient peoples, whose cultures and languages have long since died.
"It is not I who makes use of folk music. It is folk music that makes use of me," he was quoted as saying on several of his albums.
Born Aug. 7, 1930, Tormis got his diploma from the Moscow Conservatoire in 1956, wrote symphonic music and other mainstream forms early in his career, but increasingly focused on ancient forms after researching music going back centuries of the Estonians and Finns, as well their lesser-known relatives, such as the Liivs and Ingrians.
Tormis is survived by his wife, Lea, and one son, Tonu.