Pete Seeger, the legendary American folk musician and social activist, died of natural causes on Monday. He was 94.

A major influence to dozens of musicians, including Bob Dylan and Bruce Springsteen, Seeger transformed American music and helped bring folk, with its emphasis on tradition and politics, to the mainstream.

As a member of the Weavers in the 1950s, his cover of Lead Belly's "Goodnight, Irene" hit number one. Other songs that he wrote, co-wrote, or adapted include "If I Had a Hammer," "Where Have All the Flowers Gone?", "Turn! Turn! Turn!," and "We Shall Overcome." In total, he recorded more than 100 albums. He was also popular presence on television in the early 1950s.

His popularity was temporarily derailed, however, when he was blacklisted by McCarthy's House Un-American Activities Committee because of his membership in the Communist Party during the 1940s. In 1955, a defiant Seeger was called to testify before the committee.

"I feel that in my whole life I have never done anything of any conspiratorial nature," he said. "I am not going to answer any questions as to my association, my philosophical or religious beliefs or my political beliefs, or how I voted in any election, or any of these private affairs. I think these are very improper questions for any American to be asked, especially under such compulsion as this." He also offered to sing the songs that the congressmen mentioned.

For this, he was indicted on 10 counts of contempt of congress. He was convicted in 1961 and sentenced to one year in prison, though the charges were later dismissed. To survive the blacklisting, he played up to four shows a day at colleges, coffee houses, and churches around the country, often for just $25 a show.

A dedicated political activist, Seeger performed for the labor movements of the 1940s and 1950s, the civil rights battles of the 1950s and 1960s, and the anti-Vietnam War protests in the late 1960s and early 1970s.

"I still believe the only chance for the human raced to survive is to give up such pleasures as war, racism and private profit," he told Rolling Stone in 1979. He remained active in progressive causes until the end of his life, even performing at an Occupy Wall Street rally in 2011 at the age of 92.

Music and politics were part of Seeger's life from the beginning. Born May 3rd, 1919, his father was an ethnomusicologist who taught at Yale and Julliard and an anti-war activist. His mother, Constance de Clyver Edson Seeger, was a concert violinist.

His father, along with John and Alan Lomax, was one of the first to collect and transcribe American folk music. Later, after he dropped out of Harvard—where he founded a leftist paper and joined the Young Communist League—Alan Lomax introduced Seeger to legendary folk musician Lead Belly and helped him find a job at the Archive of American Folk Song at the Library of Congress in New York City.

Not long after, Seeger met and befriended Woody Guthrie, and the two travelled across the country, performing for labor groups. Seeger co-founded the Weavers in 1948, with whom he had several major hits. After the blacklisting, his career again flourished during the 1960s when he, along with Bob Dylan, Joan Baez, Peter, Paul, and Mary, and others, led a folk revival. Seeger's reaction to Dylan's famous "electric" performance at Newport Folk Festival in 1965 has become the stuff of legend; rumor had it that an enraged Seeger attempted to cut the power cords with an axe, though witnesses and Seeger later disputed that account. He did, however, call the performance "some of the most destructive music this side of hell."

Seeger's wife, Toshi died last year, just days before their 70th anniversary. Seeger is survived by his son, Daniel; his daughters Mika and Tinya; and six grandchildren.

Below, video of Seeger playing at President Obama's first inauguration in January 2009.

[Image via Getty]