Decades before NFL player Colin Kaepernick took a knee during the national anthem to protest police treatment of African-Americans, boxer Muhammad Ali roiled white America with his 1967 resistance to the Vietnam War draft.
The boxer had converted to the Nation of Islam a few years earlier, and he explained his resistance to the war by saying, "I ain't got no quarrel with them Viet Cong."
Ali's resistance to the draft resulted in his being stripped of his heavyweight title, banned from boxing and charged with evasion. (Though he avoided jail time, it would be more than three years before he returned to the ring.) Biographer Jonathan Eig says Ali's protest was unprecedented in those days.
"It was unimaginable for most black athletes to stand up that way and say, ... 'I'm going to play by my rules and to criticize presidents and to criticize the war and to call all of white America a fraud,'" Eig says. "That was radical."