Last week I found myself sitting in an auditorium on the UNC campus listening to an undergraduate lecture on American history since the Civil War. Both the course and the lecturer, Matt Andrews, had come highly recommended, and on this day, Andrews was doing one of the things he does best — using sports to illustrate the history of race relations in the United States.

This particular lesson focused on boxing.

Prizefighting, Andrews explained, became popular in the mid-1800s as a white man’s sport, one that pitted native-born Americans against Irish immigrants. As it evolved through the post-Civil War years, white boxers, especially those at the heavyweight level, refused to get in the ring with a black opponent.

Against this backdrop, a man named Jack Johnson emerged as a heavyweight contender through a parallel world of African American fighters. Born and raised in Galveston, Texas, Johnson was a stubborn man who flaunted conventions in every possible way.

He taunted white fighters in the ring, Andrews said. He had open relationships with white women, including his three wives; dressed in expensive suits; wore diamond jewelry; and drove fast cars.

According to filmmaker Ken Burns, Johnson “was everything that a black man of his era was not supposed to be: outspoken, articulate, intelligent, powerful, wealthy, good-looking and charming.”

Burns directed a 2005 PBS documentary about Johnson called “Unforgivable Blackness,” a phrase coined by NAACP founder W.E.B. Du Bois to describe the backlash Johnson faced throughout his life as he attempted and increasingly succeeded in demonstrating that as a prizefighter and a human being he was the white man’s equal.

Much like the film, Andrews’ lecture illustrated how Johnson, with his stubborn refusal to play by society’s rules, was able to break through the “color line” that once existed in heavyweight boxing.

Johnson’s first triumph came after he spent two years stalking, taunting, and challenging then heavyweight champion Tommy Burns, who ultimately relented and agreed to fight Johnson on Boxing Day (Dec. 26) 1908 in Sydney Australia.

Johnson knocked burns out in the 14th round, becoming the first African American heavyweight champion in U.S. history.

Retaining that title, however, would prove to be his biggest battle.