Arydell Spinks had 12 children, but on October 22, 1963, seven of them missed school.

“If they miss tests scheduled for that day and are marked ‘truant,’ that’s just too bad,” wrote the Chicago Defender in an article about Spinks’ plan to keep her kids home from school.

Spinks’ children weren’t contending with stomach bugs—they were boycotting school segregation in Chicago’s public schools. They were part of “Freedom Day,” a massive, but little remembered attempt to obtain educational equity in Chicago’s fragmented school district. The protest, which was supported by Martin Luther King Jr., involved over 200,000 children and tens of thousands of adults.

The protest was designed to call attention to segregation in Chicago schools. Nearly a decade earlier, Brown v. Board of Education of Topeka had made segregated public education unconstitutional. But though Chicago schools didn’t have an overt segregation policy, they were still starkly divided between Black and white students.

Schools in Black neighborhoods were in much worse condition than those in white neighborhoods. Many schools were so crowded that students had to attend in shifts; by 1960, up to 33,000 Black students only attended school for four hours a day so that their schools could accommodate all their enrolled students. Auditoriums, basements, cafeterias and even hallways became classrooms. Supplies were at a premium.

Benjamin Willis, the Chicago Public Schools superintendent, refused to address what amounted to de facto segregation. When asked why Black schools were so much more run-down than white ones, writes historian John L. Rury, Willis “claimed not to know how many Black or White students were enrolled in particular schools, since the district maintained ‘no record of race, color or creed of any student or employee.’”

Willis was heralded for improving conditions in schools in majority-white areas, but schools in Black areas became even worse. At the height of the crisis, class sizes were 25 percent larger in African-American schools, Black students received only two-thirds of the expenditures received by white students, and many classes in black schools were crammed with over 40 students at a time.

The huge gaps between schools in Chicago was due, in part, to a discriminatory practice called redlining, which allowed for more investment in majority-white areas. In the 1930s, the Federal Housing Administration began using methods that drew “red lines” around poor, majority-Black neighborhoods and funneled lending dollars and good insurance to white areas instead. In the years after World War II, Chicago’s white population moved to majority-white suburbs while its urban areas languished.

Meanwhile, Chicago’s African-American population swelled with the Great Migration, a massive movement of millions of Black people from the South to cities in the North and West. Between 1915 and 1950, more than 500,000 Black people flooded into Chicago.

As they settled in crowded, majority-Black neighborhoods, public schools became overcrowded and run down. White neighborhoods—upheld by strictly drawn school district boundaries that excluded kids from different neighborhoods—had well-kept, orderly schools. But Black neighborhoods had just the opposite.

There was a seeming solution: Bus Black students to majority-white schools to even out the balance. But Willis refused to do so, and staunchly refused to let students from schools in majority-Black areas transfer to white schools. Instead, he built a handful of new schools in Black districts.

Then, in 1961, he proposed that Black schools experiencing crowding move students into aluminum mobile classrooms. These “Willis Wagons,” as they were derisively termed, were seen by the African-American community as just another way to keep Black students corralled in poor schools.

“When a Black school that was close to a white school became overcrowded, rather than permitting the Black kids to cross a block and go to the white schools, the Willis Wagons were put up on the campuses of the Black schools in order to contain them,” Bob Lucas, a community organizer, told the producers of the ’63 Boycott project.

Finally, in 1963, tensions boiled over. Community members began burning Willis Wagons and picketing Willis’s home. They began to plan a protest that would expose the conditions of the schools to one and all. A communitywide coalition of groups organized a mass boycott they called “Freedom Day.” Martin Luther King, Jr., who had spoken at the March on Washington a few months before, met with organizers and encouraged them to protest the inequality in their schools.

On the day of the boycott, 225,000 students—half of the entire school district— stayed home from school despite threats of reprisals by teachers and school administrators. Ten thousand people crowded around City Hall and the Board of Education building, demanding integration of the city’s schools. And organizers gave protesting kids the opportunity to attend “Freedom Schools”—ad-hoc schools offering a Civil Rights-themed curriculum.

The day after the protest, The Chicago Defender, a legendary African-American newspaper, proclaimed the boycott “a thumping success.” “225,000 KIDS MAKE WILLIS EAT JIM CROW,” it blared. Meanwhile, Chicago’s predominantly white papers were filled with letters to the editor from disgusted Chicagoans. “The mass boycott…served at least one purpose—it instilled in the minds of approximately 200,000 children that it is not necessary to adhere to laws or rules,” wrote one citizen.

The protests made school conditions the talk of Chicago—but they didn’t make much difference to the city’s unequal school situation. Willis stayed in office until 1966, and other school board members—appointed by Mayor Richard Daley, who was often accused of trying to push African-Americans out of Chicago entirely—upheld Willis’s policies. Schools in majority-Black neighborhoods continued to languish.

The situation became even bleaker with every passing year. “The broken windows were there,” one teacher at DuSable High School wrote in the early 1970s, “along with the torn window shades and broken desk tops, appendages to the badly lighted, worn central hallway.”

Later, teachers went on strike and the school system degraded. It would take 25 years for Chicago to begin reforming its school system. Even now, Chicago’s school system is largely segregated, with 73 percent of all new school construction occurring in majority white areas. Chicago’s school boycott may not have effected immediate change, but it was the first foray in an ongoing battle.

For Spinks, it was worth it. “It’s just asking so little of us,” she told the Chicago Defender. “I would keep them home for a week if I felt it would help the cause of equal educational opportunity.”