On March 2, 1955, a 15-year-old Black high school junior named Claudette Colvin boarded a segregated city bus in Montgomery, Alabama, taking a window seat near the back. When the driver ordered her to give up her seat so a White woman could be more comfortable, Ms. Colvin — who had been studying Black history in class, learning about abolitionists like Harriet Tubman and Sojourner Truth — did not budge.

“History had me glued to the seat,” she said later, recalling how it felt as though Tubman and Truth had their hands on her shoulders, giving her “the courage to remain seated.”

History would record that it was Rosa Parks, the longtime secretary of the local NAACP, who helped kick-start the modern civil rights movement by refusing to give up her seat on a crowded Montgomery bus.

Yet it was Ms. Colvin, nine months earlier, who engaged in one of the first defiant challenges to the city’s Jim Crow transit system, remaining in her seat until police dragged her backward off the bus.

While Parks’s stand proved far more consequential, leading to a year-long bus boycott that thrust the Rev. Martin Luther King Jr. to national prominence, Ms. Colvin’s arrest inaugurated what King described as a pivotal period for Black people in Montgomery. Community leaders formed a committee to meet with city and bus company officials, calling for improved treatment for Black passengers. Those discussions proved fruitless, King recalled in a memoir, but “fear and apathy” gradually gave way to “a new spirit of courage and self-respect.”