Founded by activists associated with the Fellowship of Reconciliation (FOR), an interfaith pacifist organization, the group was influenced greatly by the teachings of Gandhi and, in the early 1940s, worked to integrate Chicago restaurants and businesses using sit-ins and other nonviolent actions, according to the Martin Luther King Jr. Research and Education Institute at Stanford University.

CORE’s 1947 Journey of Reconciliation, an integrated, multi-state bus ride through the upper South, “was met with minimal violence, although several of the riders were arrested, and two were sentenced to work on a chain gang in North Carolina,” the institute writes.

A pillar of CORE's principles was a strict devotion to interracial membership, historian Brian Purnell writes in his book Fighting Jim Crow in the County of Kings. “CORE hoped to create an interracial, nonviolent army that would end racial segregation in America with campaigns that employed what Gandhi called satyagraha, which translates as 'soul force' or 'truth force.' CORE founders believed that local chapters' public displays of interracial solidarity and disciplined use of nonviolence would transform America into a truly colorblind democratic society."

In its first few years, according to Purnell, local CORE chapters were formed in 19 cities, including Baltimore, Chicago, Columbus, Cleveland,Denver, Detroit, Los Angeles and New York, although many didn’t last long.

“Their victories were often limited in scope,” he writes. “CORE chapters might successfully desegregate a downtown roller-skating rink or open up housing for a handful of Black people, but the process CORE chapters had to follow was prolonged and laborious."

By the end of 1954, many CORE chapters were disbanded, but, according to the Chicago Public Library, the organization found new dedication following the Brown v. Board of Education Supreme Court decision made that same year. “CORE decided to channel the majority of its energies on the South,” the library notes, supporting sit-ins and sending field secretaries to advise activists on nonviolent protest methods.

Spurred by Rosa Parks, who, in 1955 was arrested for refusing to give up her seat on a Montgomery, Alabama bus, CORE supported a boycott of the city's busses, leaving them with low ridership for a year. In 1956, the Supreme Court ruled the state's bus segregation laws were unconstitutional.

The boycott became a model for civil disobedience in the civil rights movement, and, the King institute notes, CORE promoted King’s work during the bus boycott, adding that in October 1957 the leader agreed to serve on the CORE advisory committee.

King’s Southern Christian Leadership Conference (SCLC) went on to work with CORE on several projects, including the support of integrated education, voter education and the Chicago Campaign.

CORE’s national director, James Farmer, organized the Freedom Rides in the spring of 1961, with a mission of testing two Supreme Court rulings, according to The New York Times: Boynton v. Virginia, which desegregated bathrooms, waiting rooms and lunch counters, and Morgan v. Virginia, which desegregated interstate buses and trains.

“The Freedom Rides took place as the Civil Rights movement was gathering momentum, and during a period in which African-Americans were routinely harassed and subjected to segregation in the Jim Crow South,” the Times reports.

Thirteen Black and white women and men took part in the original Freedom Ride, heading south from Washington, D.C., including future civil rights leader and U.S. Representative John Lewis.

According to the Global Nonviolent Action Database, the volunteers received intensive training. “As an interracial group their intention was to sit wherever they wanted on buses and trains as well as to demand unrestricted access to terminal restaurants and waiting rooms,” it states.

The movement and participants grew, as did arrests, mob violence and police brutality.

King was in support of the Freedom Rides, but didn’t participate personally because of the danger involved.

“In Anniston, Alabama, one bus was firebombed, and its fleeing passengers were forced into an angry white mob,” the King Institute writes. “As the violence against the Freedom Rides increased, CORE considered halting the project. A Freedom Ride Coordinating Committee was formed by representatives of the Student Nonviolent Coordinating Committee, CORE, and SCLC to sustain the rides.”

The attacks were widely reported on by the media, but, according to the Times, they caused Farmer to end the campaign: “The Freedom Riders finished their journey to New Orleans by plane.”

But the efforts and nationwide attention did help bring change. On Sept. 22, 1961, Attorney General Robert Kennedy ordered the Interstate Commerce Commission to end interstate bus terminal segregation. The Civil Rights Act of 1964, ending segregation in public places nationwide, was passed three years later.

Following the Freedom Rides, CORE concentrated on voter registration and co-sponsored the March on Washington in 1963, where King famously delivered his "I Have a Dream" speech.

As part of the 1964 Freedom Summer voter-registration drive in Mississippi, CORE members James Chaney, Andrew Goodman and Michael Schwerner (Goodman and Schwemer were white, Chaney was Black) were stopped for speeding on June 21, 1964. In events that inspired the 1988 movie Mississippi Burning, it was reported that the men had earlier visited a church that had been burned by the Ku Klux Klan.

Booked at the county jail and eventually fined, released and escorted by police to the edge of town, they were not seen alive again. Their bodies were found more than a month later. All had been shot to death.

In a 1967 trial, 19 men were indicted on federal charges, seven of which were convicted of civil rights violations, and with none serving more than six years.

The case was repoened years later, and, after a 2005 murder trial, former KKK leader Edgar Ray Killen was convicted on three counts of manslaughter and sentenced to 60 years in prison.

The murders, according to the King Institute, left many activists “disenchanted” with the nonviolence methods employed by groups like CORE.

“By 1966 a power struggle within CORE forced Farmer to step down as national director, leaving the more militant Floyd McKissick in his place,” it states. “After King worked with McKissick during the summer of 1966 on the Meredith March Against Fear, CORE adopted a platform based on Black Power and limited white involvement in the organization.”

After King’s assassination in 1968, McKisick told the New York Times April 4, 1968 that King "was the last prince of nonviolence. ... Nonviolence is a dead philosophy, and it was not the Black people that killed it. It was the white people that killed nonviolence and white racists at that."

Roy Innis, elected CORE's national director in 1968, called the group "once and for all a Black nationalist organization,” according to the New York Times, and promoted segregated education and conservative Republican policies and candidates. A polarizing figure, his leadership caused Farmer and other CORE members to leave the group.

Congress of Racial Equality (CORE), The King Institute

Fighting Jim Crow in the County of Kings by Brian Purnell

The Montgomery Bus Boycott, nps.gov

Global Nonviolent Action Database

These Slain Civil Rights Workers Are Getting the Presidential Medal of Freedom, Time

Who Were the Freedom Riders?, The New York Times

Robert F. Kennedy Human Rights

Edgar Ray Killen, convicted of 1964 'Mississippi Burning' killings, dies at 92, NBC News