Lawrence Guyot, a leader of the civil rights movement of the 1960s who survived brutal jailhouse beatings in the South, has died from heart disease and diabetes. He was 73.

His daughter Julie Guyot-Diangone announced the news on Saturday although it was unclear if he died on Thursday night or Friday, according to the Associated Press. Guyot passed away at his home in Mount Rainier, Md., after a life that saw him on the front lines of the fight for equality.

Guyot rose to prominence as the director of the Freedom Summer Project in 1964, an effort that registered thousands of black voters in the face of a century of intimidation and violence by the white establishment. He had previously been involved with the Student Nonviolent Coordinating Committee, which was one of the leading civil rights organizations in the Deep South.

“He was a civil rights field worker right up to the end,” Guyot-Diagnone said.

The Washington Post reported Guyot was also the founder of the Mississippi Freedom Democratic Party, which tried to seat an integrated delegation at the 1964 Democratic National Convention in opposition to the segregationist Dixiecrats.

It was an arrest in 1963, though, that would propel Guyot’s name into the history books. After being arrested along with several other civil rights demonstrators he was held at a Winona, Miss., jail, where the guards took him out of his cell and into the hands of a mob of white men waiting behind the building.

“Now you know what he looks like,” the jailer told the crowd, according to the Post. “You can take care of him whenever you find him.”

The guards then escorted back Guyot inside and left his cell door unlocked, although if he were to leave he knew he would have been killed. The open door provided access to anyone who wanted to come in.

“His face looked like a piece of raw steak,” civil rights leader Dorie Ladner said of the night Guyot was released. “He was convinced that they were going to kill him, but [NAACP leader] Medgar Evers had been killed that night, and they let him and four women go.”

Guyot would later move to Washington, working on behalf of disenfranchised black voters across the country. In his later years, Guyot would defend the civil rights movement when pressed by Bill O’Reilly and Sean Hannity of Fox News but never seemed to lose his revolutionary spirit.

The AP noted that Guyot’s daughter recently saw him on a bus questioning young people about their political views. He was an early advocate of gay marriage and married a white woman when interracial marriage was still illegal in many states.

“He followed justice,” his daughter said. “He followed what was consistent with his values, not what was fashionable. He just pushed people along with him.”