George White was critically injured. But when surgeons in his Atlanta hospital found out he had black ancestry, they kicked him out mid-examination, shipping him across the street to a black hospital despite the pouring rain. He died in the overcrowded, underfunded hospital days later. The year was 1931, and like hundreds of thousands of other black people in the segregated South, White was a victim of Jim Crow segregation laws.

Between the 1870s and the 1960s, Jim Crow laws upheld a vicious racial hierarchy in southern states, circumventing protections that had been put in place after the end of the Civil War—such as the 15th Amendment, which gave black men the right to vote 150 years ago this week. The discriminatory laws denied black people their rights, subjected them to public humiliation, and perpetuated their economic and educational marginalization. Anyone who challenged the social order faced mockery, harassment, and murder.

The term has origins in the 1820s, when white comedian Thomas Rice created the character “Jim Crow.” The stereotypical character became both a stock figure in minstrel shows and a widely used nickname for black people.

View Images Dismantling Jim Crow laws was a major goal for Martin Luther King Jr., pictured above marching in Washington in 1963, and for the civil rights movement. The laws denied people of color their rights, subjected them to public humiliation, and perpetuated their economic and educational marginalization. Photograph by National Archive, Newsmakers/Getty

After the Civil War ended, the 13th Amendment formally abolished slavery in the United States. But white citizens in the former Confederacy resisted emancipation and quickly acted to deny black people their new freedoms. Using former slave laws as their template, they enacted “black codes” that denied black people everything from property ownership to free movement to business ownership. Historian Daniel A. Novak describes the codes as “intended to produce…a close approximation of the now forbidden master-slave relationship.”

In response to northern outrage about these codes, Congress passed constitutional amendments, now known as the Reconstruction Amendments, designed to guarantee the freedom and civil rights of formerly enslaved people. The 14th Amendment guaranteed citizenship and equal protection under the law, and the 15th Amendment prohibited denying voting rights based on “race, color, or previous condition of servitude.”

Southern states had to ratify the amendments to be readmitted to the Union. But though states grudgingly complied with federal law, they undid as few black codes as possible. Meanwhile, groups like the Ku Klux Klan intimidated and killed black people who challenged the now-unwritten laws of conduct.

View Images In December 1955, Rosa Parks refused to give her seat to a white passenger on a segregated bus in Montgomery, Alabama. Her arrest inspired the Montgomery Bus Boycott that ended when the Supreme Court ruled that Montgomery's segregated buses were unconstitutional. Photograph by Bettmann, Getty

In 1877, new president Rutherford B. Hayes followed through on a promise to stop federal intervention in the South. Swiftly, southern states reversed Reconstruction-era laws and established new segregation laws in their place. After the Supreme Court ruled “separate but equal” facilities legal in Plessy v. Ferguson in 1896, the floodgates opened. Southern states implemented hundreds of laws mandating different treatment for black and white citizens.