The growth of American industrial might in the 1870s and 1880s was paralleled by the emergence of unions representing the workers. and other unions was to achieve the eight-hour day.On May Day 1886, the workers at the McCormick Harvesting Machine Co. in Chicago began a strike in the hope of gaining a shorter work day. On May 3, police were used to protect strikebreakers and a scuffle broke out; one person was killed and several others injured.The following day, May 4, a large rally was planned by anarchist leaders to protest alleged police brutality. The gathering was peaceful until a police official, in contravention of the mayor's instructions, sent units into the crowd to force it to disperse. The police fired into the crowd of workers, killing four.A period of panic and overreaction followed in Chicago. Four were hanged in November 1887, one committed suicide and three were later pardoned by Illinois governor, John Peter Altgeld.Clearly the ranks of the Knights of Labor and other unions were filled with many socialists and anarchists; some were committed to violent disruption of the capitalist system. Widespread fear of unionism and other radicalism influenced most of the public to support harsh treatment of the accused.The Haymarket Riot was a signal event in the early history of American labor. and moved toward the more moderate American Federation of Labor. For many years the police at Haymarket Square were regarded as martyrs and the workers as violent anarchists; that view moderated to a large extent in later times.