"Eight hours shall constitute a legal day's labor from and after May 1, 1886" proclaimed the Federation of Organized Trades & Labor Unions (FOTLU) at their 1884 convention. The next year, FOTLU, later to become the American Federation of Labor, and the Knights of Labor, reiterated their demand for a reasonable work day and pledged their support with strikes and demonstrations. At the time, there were no laws or contracts for a forty-hour work week, maximum hours, minimum wages or child labor prohibitions. Workers were completely at the mercy of employers.
On May 1, 1886, Chicago unionists and ordinary workers made the city the center of the national movement for an eight-hour day. Between April 25 and May 4, workers attended scores of meetings and paraded through the streets. 35,000 workers walked off their jobs on Saturday, May 1. Tens of thousands skilled and unskilled workers joined them on May 3 and 4. Many demanded eight hours' work for ten hours' pay. Police clashed with strikers. At the McCormick reaper plant, a long-simmering strike erupted in violence on May 3, and police killed two strikers. A protest meeting was called at the West Randolph Street Haymarket at Des Plaines Street.
A peaceful crowd gathered on the evening of May 4th. Mayor Carter Harrison attended and instructed police not to disturb the meeting. Nearing the meeting’s end, Inspector John Bonfield ordered 176 officers to disperse the gathering. Someone, unknown to this day, hurled a bomb, killing one officer instantly. Police drew guns, firing wildly. Sixty officers were injured, and eight died; most likely shot by other officers in the chaos. An undetermined number of the crowd were killed or wounded.
Police arrested hundreds of people. Eight labor activists were put on trial, some who weren’t present during the crime. Lacking evidence and without the bomber, the prosecutor instructed the cynically packed jury to adopt a conspiracy theory and convict all eight. Seven were sentenced to death and one to fifteen years of hard labor. The trial ranks as one of the worst miscarriages of justice in U.S. history.