Sixty years ago this month, in May 1963, police in Birmingham, Alabama, used clubs, fire hoses, and dogs to attack crowds of Black people demonstrating against racial segregation. The images of canines mauling protesters, ripping their clothes and biting their bodies, are some of the most disturbing visuals of the entire civil rights movement.

A photograph of officer Dick Middleton setting a dog upon 15-year-old Walter Gadsden appeared on the front page of the New York Times, the Los Angeles Times, and the Washington Post on May 4. Newspapers in Asia, Europe, Africa, and Latin America followed suit, prominently featuring pictures of Birmingham’s K-9s attacking protesters. Concerned about damage to the country’s reputation, the United States Information Agency conducted a study of global coverage of the events in Birmingham, concluding that “pictures of police brutality, particularly the use of police dogs, has militated strongly against the U.S. image.” The outcry was compounded by the fact that many of the protesters were school-age, as Martin Luther King Jr.’s lieutenant James Bevel had organized thousands of students to march in the “Children’s Crusade” against Jim Crow.

The attacks by Birmingham’s police dogs prompted three main responses from Americans. Conservative critics of the civil rights movement defended the dogs as a necessary law enforcement tool against criminals. Many white liberal observers in the North, by contrast, decried them as cruel weapons of a renegade police force, while insisting that the Birmingham police were a department of “bad apples” amid an otherwise honorable profession.

But it was civil rights organizers themselves whose response was most consequential. The dog attacks in Birmingham offered activists in the South and North a political language for analyzing police abuses within the larger context of Black people’s pursuit of freedom and equality.

In Philadelphia, NAACP picketers demanded “rights not bites,” while protesters in New York denounced “dog government in Alabama.” Some argued that Alabama authorities were not the only ones bearing responsibility for the attacks and highlighted the presence of the dogs to sharpen their critiques. As James Baldwin told a rally of predominantly white marchers in Los Angeles, “Those crimes in Birmingham, those dogs and fire hoses, are being committed in your name.” A headline in Baltimore’s Afro-American newspaper captured the mood: “B’ham’s Police Dogs Shock World.”

Indeed, just as horrific videos of police killing Eric Garner, George Floyd, and Tyre Nichols would galvanize protests across the country and globe decades later, the outrage in the wake of the news of Birmingham’s K-9 unit brutalizing protesters as young as 4 injected a local movement into the national, and even global, consciousness.

And yet, as Birmingham’s police dogs have endured as powerful symbols of backlash against the civil rights movement, their origins have largely escaped scrutiny.