C.T. Vivian, a close aide to Martin Luther King, Jr. and pioneering strategist of the civil rights movement, was laid to rest in an Atlanta funeral service on Thursday. Vivian was a master of organizing nonviolent direct actions, sacrificing his safety to help end racial segregation in the South.

In an article for The Undefeated, Saida Grundy, assistant professor of sociology & African American studies at Boston University, writes about the man who put his body on the line to expose racial injustice.

Courage is a word that describes Vivian well. Perhaps his most famous moment in the movement was during a fiery showdown against the notoriously brutish Selma, Alabama, sheriff Jim Clark. As he had done in so many counties before, Vivian was registering Black voters. Vivian’s efforts had sent 1,400 Black Selma residents down to the courthouse to register since arriving in Selma, and Clark ordered a snaking line of 100 of them off the premises that rainy day.

“You can turn your back on me,” Vivian fired at the sheriff, pointing his finger. “But you cannot turn your back upon the idea of justice. You can turn your back now and you can keep your club in your hand, but you cannot beat down justice.” Clark responded by slugging Vivian in the face, sending his lanky body flailing down the courthouse steps. Vivian was arrested, but his strategy won the day. His actions had provoked exactly the revelation of white Southern brutality that he knew could not be ignored when broadcast into televisions across the country. He succeeded in proving that Black liberation exposed what the Jim Crow South was.

Former President Barack Obama honored Vivian with the Presidential Medal of Freedom in 2013. “He was always one of the first in the action — a Freedom Rider, a marcher in Selma, beaten, jailed, almost killed, absorbing blows in hopes that fewer of us would have to,” Obama wrote shortly after Vivian’s death.

“He waged nonviolent campaigns for integration across the south, and campaigns for economic justice throughout the north, knowing that even after the Voting Rights Act and Civil Rights Act that he helped win, our long journey to equality was nowhere near finished.”