Representative John Lewis, longtime congressman and Civil Rights Movement luminary, died Friday following a battle with pancreatic cancer. He was 80 years old.

“It is with inconsolable grief and enduring sadness that we announce the passing of U.S. Rep. John Lewis,” his family said in a statement. “He was honored and respected as the conscience of the U.S. Congress and an icon of American history, but we knew him as a loving father and brother. He was a stalwart champion in the ongoing struggle to demand respect for the dignity and worth of every human being. He dedicated his entire life to nonviolent activism and was an outspoken advocate in the struggle for equal justice in America. He will be deeply missed.”

Lewis, who protested alongside Martin Luther King and braved state violence on “Bloody Sunday,” the 1965 voting rights march from Selma to Montgomery, was an activist who helped galvanize some of the most important movements for racial equality. He was the last surviving speaker of the 1963 March on Washington, which he helped organize, and where King delivered his historic “I Have a Dream”speech.

In December, Lewis announced that he was battling stage 4 pancreatic cancer.

“I have been in some kind of fight—for freedom, equality, basic human rights—for nearly my entire life. I have never faced a fight quite like the one I have now,” Lewis said in a statement at the time. “While I am clear-eyed about the prognosis, doctors have told me that recent medical advances have made this type of cancer treatable in many cases, that treatment options are no longer as debilitating as they once were, and that I have a fighting chance.”

The announcement of Lewis’s death followed earlier news Friday of the passing of another civil rights leader, Rev. C.T. Vivian.

Lewis was born on February 21, 1940, to Eddie and Willie Mae Carter, sharecroppers who owned their own farm in rural Alabama. One of ten children, he was known among those who loved him as “Preacher,” after he famously baptized and ministered to the farm’s chickens. The story is immortalized in a children’s book, Preaching to the Chickens: The Story of Young John Lewis, by Jabari Asim.

“I could imagine that they were my congregation,” he wrote in his 1998 memoir, Walking With the Wind. “And me, I was a preacher.”

As a theological student in Nashville, he met one of his mentors, Rev. James Lawson, Jr., who taught him the meaning of civil disobedience. Soon, Lewis was among early students to protest the city’s segregated lunch counters. Later, he would help found the Student Nonviolent Coordinating Committee (SNCC).

He became one of the original 13 Freedom Riders, a multiracial coalition of activists who challenged segregation across southern state lines. Lewis braved multiple brutal physical attacks against his body in his long protesting career. According to The New York Times, he was arrested 40 times over the period of 1960 to 1966, and spent 31 days in Mississippi’s infamous Parchman Penitentiary.