It had started when the Pullman Palace Car Company lowered wages without lowering rents in the company town, also called Pullman. (It’s now part of Chicago.)

When angry workers complained, the owner, George Pullman, had them fired. They decided to strike, and other workers for the American Railway Union, led by the firebrand activist Eugene V. Debs, joined the action. They refused to handle Pullman cars, bringing freight and passenger traffic to a halt around Chicago. Tens of thousands of workers walked off the job, wildcat strikes broke out, and angry crowds were met with live fire from the authorities.

During the crisis, President Grover Cleveland signed a bill into law on June 28, 1894, declaring Labor Day a national holiday. Some historians say he was afraid of losing the support of working-class voters.

“There were many political advantages at that moment to provide recognition for Labor Day,” said Joshua B. Freeman, a distinguished professor of history at Queens College and the City University of New York Graduate Center.

But it wasn’t the only workingman’s holiday on the table. Starting in 1884, the labor movement had called for strikes and protests on May 1 to push for an eight-hour workday. That would-be holiday was called May Day, and it’s now celebrated around the world, though it’s not officially recognized in the United States.

You might blame the Haymarket affair. On May 4, 1886, a bomb went off at a demonstration in Chicago’s Haymarket Square in support of an eight-hour workday and against police killings of protesters. The authorities opened fire in response, and seven officers and four protesters were killed.