In 1867, the Illinois Legislature passed a law mandating an eight-hour workday. The legislation may have been intended to hand a victory to workers, but employers simply refused to cooperate.
On May 1, 1867, a citywide strike in Chicago devolved into bedlam as police clashed with demonstrators. Police suppressed the strikers with force, effectively allowing private employers to continue skirting state law.
In 1869, President Ulysses S. Grant issued a proclamation that guaranteed both a stable wage and an eight-hour workday, but it only applied to government employees. Workers in private enterprise hoped they could get the same legal guarantees in a national law.
In the 1870s and 1880s, the eight-hour workday became a key demand of labor unions across the country. The National Labor Union had dissolved, but in its place rose other groups, such as the Knights of Labor and later the Federation of Organized Trades and Labor Unions (the precursor to today's American Federation of Labor and Congress of Industrial Organizations, or AFL–CIO). May 1 also became an annual day in which to organize strikes and hold demonstrations in support of the movement. As workers' demands were continuously rebuffed, calls came for an armed uprising.