Which 1886 uprising at Haymarket Square influenced the creation of International Workers’ Day?

The Haymarket affair was the 1886 uprising at Chicago’s Haymarket Square that influenced the creation of International Workers’ Day.

A labor demonstration on May 4, 1886, protested police violence during the campaign for an eight-hour workday. As police moved to disperse the gathering, someone threw a bomb into their ranks. Gunfire followed, and several police officers and civilians died, although the exact number and circumstances of many deaths remain contested.

Eight anarchists were tried in a case widely criticized for its weak evidence linking them to the bomb thrower. Four were eventually executed, one died by suicide before execution, and the remaining defendants were later pardoned by Illinois Governor John Peter Altgeld. The affair damaged the public image of the labor movement but became a lasting symbol of workers’ rights. May 1 was later associated internationally with labor demonstrations, although the United States does not observe it as a federal holiday.