Having skipped an earlier bus that was too crowded, Rosa Parks was relieved to see plenty of empty seats on the next Montgomery city bus that came to her stop. She walked past several empty seats and sat down just past the movable sign that read “Colored.”

The year was 1955. Although African Americans had been free from slavery for 90 years, Montgomery, Alabama, enforced some of the country’s strictest segregation laws. Meant to keep African Americans separated from whites, these so-called Jim Crow laws angered Parks. A few years earlier she had joined the National Association for the Advancement of Colored People (NAACP), an organization that tried to protect African American rights. The NAACP had convinced the U.S. Supreme Court that it was unconstitutional to separate public school children based on race.

The bus Parks was riding on began to fill up. At one stop four white passengers boarded. Three took seats at the front, and one man grabbed the rail to ride standing.

The driver twisted around in his seat. Looking at Parks and the other African American passengers, he barked, “Move, y’all. I want those seats.” Parks’s eyes widened. It was James F. Blake, the same man who had once before ordered her off a bus he was driving. Blake’s scowl sent Parks’s mind tumbling back to that incident 12 years earlier.

Montgomery bus drivers used their own discretion in how they enforced the city’s segregation rules. Some disregarded the rules. Other drivers, including Blake, required African Americans to pay their fare at the front of the bus, exit, and then reboard at the back to find a seat. Blake had a reputation of driving off before riders could reboard the bus.

On that day 12 years earlier in 1943, Parks had refused to exit and reboard at the rear because the back aisle was already crowded with standing passengers. When Blake insisted, Parks responded that she was already on the bus and didn’t understand why she had to get off just to get back on. Blake ordered her off. Rather than disgrace herself by obeying his petty demand, Parks left, vowing to never again ride a bus driven by Blake. But this day she hadn’t noticed who the driver was.

“Y’all better make it light on yourselves and let me have those seats,” Blake growled when nobody moved. Since African Americans weren’t allowed to sit in the same row as white passengers, Blake ordered everyone in the row to stand. Finally the two women across the aisle from Parks stood. Then the man next to Parks stood too. “Are you going to stand up?” Blake asked Parks, who replied that she wasn’t. “I’m going to have you arrested,” Blake stammered.

Parks didn’t want to go to jail, but she had had enough. She wanted to be treated like a human being. “You may do that,” she replied calmly. The police arrived within minutes. One policeman, F. B. Day, asked Parks why she had refused to stand. Parks replied with a question that Day couldn’t answer.

“Why do you push us around?”

 Day shrugged. “I don’t know, but the law is the law, and you’re under arrest.”

Rosa Parks’s arrest led African Americans to come together in Montgomery to refuse to ride buses citywide. This protest helped give rise to the Civil Rights movement. The U.S.Supreme Court later ruled that Alabama’s segregation laws were unconstitutional.