John Sinclair, the jazz poet and activist, has died at 82. As The Detroit News reports, a representative said that he passed away from congestive heart failure at Detroit Receiving Hospital on Tuesday morning.

Sinclair was born in Flint, Michigan in 1941. After graduating from college, he moved to Detroit and became an important countercultural figure. He wrote for the Fifth Estate, assisted in organizing the Detroit Artists Workshop Press, and co-founded the Ann Arbor Sun. In the mid-60s, he met the members of MC5 and served as their manager from 1967 to 1969. Though they parted ways after only a couple of years, Sinclair was instrumental in shaping the band’s politics.

In 1969, Sinclair was arrested for marijuana possession after offering a joint to an undercover narcotics officer and was sentenced to 10 years in prison. The severity of the sentencing led to protests. Abbie Hoffman interrupted a performance by the Who at Woodstock to draw attention to Sinclair’s plight, and John Lennon recorded a song called “John Sinclair” that was later included on his 1972 album Some Time In New York City. A star-studded protest concert known as The John Sinclair Freedom Rally took place in 1971. Sinclair was released from prison a few days after the concert, after having already served two-and-a-half years.

After his release from prison, Sinclair continued his involvement in grassroots activism. He also wrote poetry set to jazz, taught classes about music history, and hosted radio programs. Over the years, he’d lived in New Orleans and Amsterdam. In 2019, when Michigan legalized recreational marijuana purchases, he was among the first to buy.