In 1962, nearly a century after the 15th Amendment sought to protect the voting rights of Black men, less than 7 percent of Mississippi’s eligible Black voters were registered to vote, the lowest rate in the country.

Even as the civil rights movement gained traction across the South, significant barriers remained in what was considered the nation’s most racially repressive state as voter registration efforts were met with violence. In response, Black activists partnered with white volunteers to organize a major civil rights campaign in 1964. Their work, during what became known as Freedom Summer, aimed to increase Black voter registration and participation in the Deep South, particularly in Mississippi.

In August 1961, Robert Moses, a Harvard Ph.D. candidate and soft-spoken activist with the Student Nonviolent Coordinating Committee (SNCC), was brutally beaten after escorting three Black men to the courthouse in an attempt to register in the small town of Liberty, Mississippi.

In 1963, the Council of Federated Organizations (COFO), a coalition of groups led by Moses and the SNCC, held a mock gubernatorial “Freedom Election” where some 80,000 Black voters symbolically cast ballots for an interracial ticket.

The parallel election held no bearing on the official outcome, but it demonstrated that Black voters, if given the opportunity, were eager to participate in the democratic process. Yet it also showed how much more work needed to be done. Volunteers were beaten, shot at and met with angry mobs. The Freedom Election, Moses said, “makes it clear that the Negroes of Mississippi will not get the vote until the equivalent of an army is sent here.”

That “army” soon arrived in the form of 700 mostly white volunteers, led by Black activists. They journeyed hundreds of miles south, where they distributed voter registration materials, set up polling stations and accompanied potential voters to courthouses. They had been trained at an Ohio college, by members of the SNCC, as well as from COFO and the Congress of Racial Equality (CORE). The volunteers also promoted the new Mississippi Freedom Democratic Party, lived among Black families, and ran Freedom Schools.

The bold initiative dreamt up by Moses, along with others including Amzie Moore, a local NAACP organizer, was called Freedom Summer, or the Mississippi Summer Project, and it laid the groundwork for sweeping change, not only in the Magnolia State, but across the country.

“Moses and Moore understood that if they could crack voting, the Black Belt would have a voice in the political process, and that would change the discrimination in the area,” explains Howard Robinson, Associate Library Director and a professor at Alabama State University who specializes in African American history and has written on the student protest movement of the 1960s.

After more than a half million Black men joined the voting rolls during Reconstruction, Mississippi led the way in devising tactics to circumvent the 15th Amendment. Those who attempted to vote might find their name in the local newspaper, be fired from their job or face threats and violence. A new state constitution adopted in 1890 also included a disenfranchisement clause that struck all voters from the rolls and then required them to register again. Only those who paid a poll tax and passed a literacy test were approved.

Black teachers, doctors and Phds routinely failed the test most whites did not have to take, according to Bruce Watson in Freedom Summer: The Savage Season of 1964 That Made Mississippi Burn and Made America a Democracy.

The majority of Freedom Summer’s white college recruits had middle- and upper-class backgrounds and hailed from places as far-flung in geography and in spirit as San Francisco and Fort Dodge, Iowa. “The idea to recruit white students was to enlarge the process,” says Robinson.

David Dennis, who led COFO’s voter education committee alongside Moses, attributes much of Freedom Summer’s success to the local families who welcomed the white volunteers into their homes like their own. White students were deeply moved by the hundreds of Black families, who, despite living in tumbledown shacks, openly shared what little they had. And Mississippi Blacks who had only known how to fear and kowtow to whites, marveled at being treated as equals for the first time.

“Living and eating together endeared the white volunteers to the Black community and the Black community to the white volunteers in ways that wouldn’t have happened otherwise,” says Robinson.

Freedom Summer also established 41 Freedom Schools across Mississippi to address what SNCC’s Charlie Cobb in 1963 referred to as an educational environment “geared to squash intellectual curiosity and different thinking.” These schools, Cobb proposed, should be designed to “fill an intellectual and creative vacuum in the lives of young Negro Mississippians” and empower them “to articulate their own desires, demands, and questions.”

In makeshift classrooms and under shady trees, volunteers taught nearly 3,000 Black youth—as well as some adults—reading, writing, math, as well as Black literature and Black history. “The curriculum looked at Africa and the Civil War and Reconstruction in different ways. It introduced young people to different vantage points for how to understand their environment,” says Robinson.

Chilling headlines soon made their way across the nation as three Freedom Summer activists—James Chaney, a Black Mississippian, and two white Northerners, Michael Schwerner and Andrew Goodman—went missing on June 21, 1964 after investigating a church burning in Neshoba County.

The FBI and National Guard mounted a massive search through back roads, swamps, and hollows. On August 4, 1964, the beaten bodies of the three men were finally found, after being killed by a Ku Klux Klan lynch mob that had the protection and help of a local policeman, revealing to the rest of the nation the depths of racial hatred in the state.

“The slaying of a Negro in Mississippi is not news. It is only because my husband and Andrew Goodman were white that the national alarm has been sounded,” Rita Schwerner told reporters during the search.

“Freedom Summer started out as a sideshow of the movement but due to the three murders, quickly took center stage throughout that summer,” says Watson.

By the end of the summer, over 1,000 people were arrested, 80 were beaten and four civil rights workers were killed. Despite those sacrifices, the efforts at first didn’t appear to make much of an impact. Although approximately 17,000 of the state’s Black residents attempted to register to vote that summer, only 1,600 of the completed applications were accepted by local registrars.

The Mississippi Freedom Democratic Party, which had been building up its membership that summer, was also dealt a significant blow. Its 68-member delegation, which included activists like Fannie Lou Hamer, were refused seats at that summer’s 1964 Democratic National Convention.

“Yes, Freedom Summer ended on sour notes. The summer was over. The MFDP got nothing but a brief moment in the spotlight. And most volunteers went home wondering if they’d done any good at all,” Watson says. “The effects took longer to sink in.”

Among the later achievements was the passing of the Voting Rights Act of 1965. Signed into law by President Lyndon B. Johnson, the act aimed to overcome legal barriers at the state and local levels that prevented African Americans from exercising their right to vote. In Mississippi alone, voter turnout among Black people increased to 59 percent in 1969.

“The Voting Rights Act of 1965 was the first, and no political change in American history has rivalled that for opening up our democracy,” Watson says.

The Freedom Summer movement also radicalized a generation of activists who went on to jumpstart the Free Speech Movement, the anti-war movement, and the women’s rights movement of the late 1960s.

And while it wasn’t immediate, “Freedom Summer truly cracked a century of Jim Crow in the most Jim Crow state in the US,” Watson says. “Within two years, Mississippi schools finally began to integrate. Within ten, there were black politicians, sheriffs, and other leaders there.”